Summary
Mozilla Thunderbird is a standalone mail and newsgroup client.
Security Fix(es):
* firefox: thunderbird: Privilege escalation in the DOM: Workers component (CVE-2026-16365)
* firefox: thunderbird: Sandbox escape in the Remote Settings Client component (CVE-2026-75874)
* firefox: Sandbox escape due to use-after-free in the DOM: Security component (CVE-2026-84121)
* firefox: Internally found bugs fixed in Firefox 155, Firefox ESR 153.2, Firefox ESR 140.15 and Firefox ESR 115.40 (CVE-2026-84145)
* firefox: Sandbox escape due to use-after-free in the DOM: Navigation component (CVE-2026-84119)
* firefox: Use-after-free in the Audio/Video component (CVE-2026-84120)
* firefox: Privilege escalation due to invalid pointer in the Graphics component (CVE-2026-84131)
* firefox: Use-after-free in the DOM: Core & HTML component (CVE-2026-84124)
* firefox: Use-after-free in the Audio/Video component (CVE-2026-84122)
* firefox: Internally found bugs fixed in Firefox 155, Firefox ESR 153.2 and Firefox ESR 140.15 (CVE-2026-84143)
* thunderbird: Uninitialized memory in MIME parsing (CVE-2026-84639)
* thunderbird: Information disclosure due to malicious IMAP server response (CVE-2026-84641)
* thunderbird: One byte overflow read in mail parser (CVE-2026-84640)
* firefox: thunderbird: Use-after-free in the SVG component (CVE-2026-92024)
* firefox: thunderbird: Mitigation bypass in the Remote Settings Client component (CVE-2026-92019)
* firefox: thunderbird: Use-after-free in the Networking component (CVE-2026-92026)
* firefox: thunderbird: Information disclosure in the Graphics: ImageLib component (CVE-2026-92031)
* firefox: thunderbird: Sandbox escape due to invalid pointer in the Graphics component (CVE-2026-92032)
* firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92010)
* firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92006)
* firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92011)
* firefox: thunderbird: Use-after-free in the DOM: Streams component (CVE-2026-92027)
* firefox: thunderbird: Use-after-free in the DOM: Core & HTML component (CVE-2026-92028)
* firefox: thunderbird: Privilege escalation in the WebExtensions component (CVE-2026-92015)
* firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92013)
* firefox: thunderbird: Use-after-free in the Disability Access APIs component (CVE-2026-92016)
* firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92012)
* firefox: thunderbird: Use-after-free in the DOM: HTML Parser component (CVE-2026-92022)
* firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics component (CVE-2026-92014)
* firefox: thunderbird: Sandbox escape in the DOM: Core & HTML component (CVE-2026-92018)
* firefox: thunderbird: Use-after-free in the JavaScript Engine: JIT component (CVE-2026-92021)
* firefox: thunderbird: Use-after-free in the Audio/Video: Web Codecs component (CVE-2026-92005)
* firefox: thunderbird: Privilege escalation in the DOM: Service Workers component (CVE-2026-92017)
* firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92009)
* firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: WebRender component (CVE-2026-92020)
* firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92008)
* firefox: thunderbird: Mitigation bypass in the DOM: Copy & Paste and Drag & Drop component (CVE-2026-92030)
* firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component (CVE-2026-92007)
* firefox: thunderbird: Use-after-free in the DOM: Navigation component (CVE-2026-92025)
* firefox: thunderbird: Use-after-free in the SVG component (CVE-2026-92029)
* firefox: thunderbird: Use-after-free in the XML component (CVE-2026-92023)
* thunderbird: Out-of-bounds read in IMAP response parser (CVE-2026-92240)
* thunderbird: Thunderbird: Out-of-bounds read via maliciously constructed IMAP line (CVE-2026-92239)
* thunderbird: Thunderbird: Memory safety violations via maliciously crafted mail headers (CVE-2026-92238)
For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
Fixed packages 1
| Release | Package | Fixed in |
|---|---|---|
| AlmaLinux · 9 | thunderbird | 140.16.0-1.el9_8.alma.1 |
Vulnerabilities 44
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Critical 10.0
Sandbox escape in the Remote Settings Client component
Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154, Thunderbird 154, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 140.15, and Thunderbird 153.2.
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Critical 9.8
Internally found bugs fixed in Thunderbird 155, Thunderbird ESR 153.2 and Thunderbird ESR 140.15
Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have bee…
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Critical 9.8
Ambiguous parsing of mail headers
A maliciously constructed mail header could lead to multiple fields being parsed as one, or potential memory safety violations. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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Critical 9.6
Sandbox escape due to use-after-free in the DOM: Navigation component
Sandbox escape due to use-after-free in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
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Critical 9.6
Sandbox escape due to use-after-free in the DOM: Security component
Sandbox escape due to use-after-free in the DOM: Security component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
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Critical 9.6
Sandbox escape in the DOM: Core & HTML component
Sandbox escape in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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Critical 9.6
Sandbox escape due to invalid pointer in the Graphics component
Sandbox escape due to invalid pointer in the Graphics component. This vulnerability was fixed in Firefox 156, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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Critical 9.1
Uninitialized memory in MIME parsing
Triggering an error condition in certain MIME bodies would cause uninitialized memory to be used. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
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Critical 9.1
Out-of-bounds read in IMAP response parser
A malicious or compromised IMAP server can trigger an out-of-bounds read in the IMAP response parser by sending an untagged '* ID' response, crashing Thunderbird. The affected parsing path is reachable before authentication. This vulnerability was fixed in Th…
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High 8.8
Privilege escalation in the DOM: Workers component
Privilege escalation in the DOM: Workers component. This vulnerability was fixed in Firefox 153, Thunderbird 153, Firefox ESR 140.15, and Thunderbird 140.15.
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High 8.8
Privilege escalation due to invalid pointer in the Graphics component
Privilege escalation due to invalid pointer in the Graphics component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
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High 8.8
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.…
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High 8.8
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.…
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High 8.8
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.…
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High 8.8
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.…
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High 8.8
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.…
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High 8.8
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.…
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High 8.8
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.…
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High 8.8
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.…
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High 8.8
Privilege escalation due to incorrect boundary conditions in the Graphics component
Privilege escalation due to incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox ESR 115.41, Firefox ESR 140.16, and Thunderbird 140.16.
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High 8.8
Privilege escalation in the WebExtensions component
Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.8
Use-after-free in the Disability Access APIs component
Use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox 156, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.8
Privilege escalation in the DOM: Service Workers component
Privilege escalation in the DOM: Service Workers component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.8
Privilege escalation due to incorrect boundary conditions in the Graphics: WebRender component
Privilege escalation due to incorrect boundary conditions in the Graphics: WebRender component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.8
Use-after-free in the JavaScript Engine: JIT component
Use-after-free in the JavaScript Engine: JIT component. This vulnerability was fixed in Firefox ESR 140.16 and Thunderbird 140.16.
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High 8.8
Use-after-free in the DOM: HTML Parser component
Use-after-free in the DOM: HTML Parser component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.8
Use-after-free in the XML component
Use-after-free in the XML component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.8
Use-after-free in the SVG component
Use-after-free in the SVG component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.8
Use-after-free in the DOM: Navigation component
Use-after-free in the DOM: Navigation component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.8
Use-after-free in the Networking component
Use-after-free in the Networking component. This vulnerability was fixed in Firefox 156, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.8
Use-after-free in the DOM: Streams component
Use-after-free in the DOM: Streams component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.8
Use-after-free in the DOM: Core & HTML component
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.8
Use-after-free in the SVG component
Use-after-free in the SVG component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.1
Mitigation bypass in the Remote Settings Client component
Mitigation bypass in the Remote Settings Client component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 8.1
Buffer overrun in IMAP
A maliciously constructed IMAP line could cause an out-of-bounds buffer read. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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High 7.5
Internally found bugs fixed in Thunderbird 155, Thunderbird ESR 153.2 and Thunderbird ESR 140.15
Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have bee…
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High 7.5
One byte overflow read in mail parser
A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
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High 7.5
Information disclosure due to malicious IMAP server response
A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response. Heap contents can ultimately be persisted to prefs.js. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
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Medium 6.5
Information disclosure in the Graphics: ImageLib component
Information disclosure in the Graphics: ImageLib component. This vulnerability was fixed in Firefox 156, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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Medium 5.4
Use-after-free in the Audio/Video component
Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
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Medium 5.4
Use-after-free in the Audio/Video component
Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
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Medium 5.4
Use-after-free in the DOM: Core & HTML component
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
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Medium 5.4
Mitigation bypass in the DOM: Copy & Paste and Drag & Drop component
Mitigation bypass in the DOM: Copy & Paste and Drag & Drop component. This vulnerability was fixed in Firefox 156, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
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Medium 5.3
Use-after-free in the Audio/Video: Web Codecs component
Use-after-free in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 156, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
References
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report
https://access.redhat.com/security/cve/CVE-2026-16365
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report
https://access.redhat.com/security/cve/CVE-2026-75874
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report
https://access.redhat.com/security/cve/CVE-2026-84119
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report
https://access.redhat.com/security/cve/CVE-2026-84120
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report
https://access.redhat.com/security/cve/CVE-2026-84121
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report
https://access.redhat.com/security/cve/CVE-2026-84122
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report
https://access.redhat.com/security/cve/CVE-2026-84124
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report
https://access.redhat.com/security/cve/CVE-2026-84131
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report
https://access.redhat.com/security/cve/CVE-2026-84143
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report
https://access.redhat.com/security/cve/CVE-2026-84145
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report
https://access.redhat.com/security/cve/CVE-2026-84639
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report
https://access.redhat.com/security/cve/CVE-2026-84640
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report
https://access.redhat.com/security/cve/CVE-2026-84641
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report
https://access.redhat.com/security/cve/CVE-2026-92005
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report
https://access.redhat.com/security/cve/CVE-2026-92006
-
report
https://access.redhat.com/security/cve/CVE-2026-92007
-
report
https://access.redhat.com/security/cve/CVE-2026-92008
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report
https://access.redhat.com/security/cve/CVE-2026-92009
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report
https://access.redhat.com/security/cve/CVE-2026-92010
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report
https://access.redhat.com/security/cve/CVE-2026-92011
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report
https://access.redhat.com/security/cve/CVE-2026-92012
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report
https://access.redhat.com/security/cve/CVE-2026-92013
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report
https://access.redhat.com/security/cve/CVE-2026-92014
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report
https://access.redhat.com/security/cve/CVE-2026-92015
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report
https://access.redhat.com/security/cve/CVE-2026-92016
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report
https://access.redhat.com/security/cve/CVE-2026-92017
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report
https://access.redhat.com/security/cve/CVE-2026-92018
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report
https://access.redhat.com/security/cve/CVE-2026-92019
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report
https://access.redhat.com/security/cve/CVE-2026-92020
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report
https://access.redhat.com/security/cve/CVE-2026-92021
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report
https://access.redhat.com/security/cve/CVE-2026-92022
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report
https://access.redhat.com/security/cve/CVE-2026-92023
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report
https://access.redhat.com/security/cve/CVE-2026-92024
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report
https://access.redhat.com/security/cve/CVE-2026-92025
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report
https://access.redhat.com/security/cve/CVE-2026-92026
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report
https://access.redhat.com/security/cve/CVE-2026-92027
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report
https://access.redhat.com/security/cve/CVE-2026-92028
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report
https://access.redhat.com/security/cve/CVE-2026-92029
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report
https://access.redhat.com/security/cve/CVE-2026-92030