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OpenAdvisories
Critical USN-7663-1 52 CVEs

thunderbird vulnerabilities

Published Jul 22, 2025 · Updated Apr 27, 2026

Summary

Multiple security issues were discovered in Thunderbird. If a user were
tricked into opening a specially crafted website in a browsing context, an
attacker could potentially exploit these to cause a denial of service,
obtain sensitive information, bypass security restrictions, cross-site
tracing, or execute arbitrary code.

Fixed packages 1

ReleasePackageFixed in
Ubuntu · 22.04 LTS 22.04:LTS thunderbird 1:128.12.0+build1-0ubuntu0.22.04.1

Vulnerabilities 52

  • Critical 9.8

    Use-after-free in XSLT

    An attacker could have caused a use-after-free via crafted XSLT data, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 135, Firefox ESR 115.20, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

  • Critical 9.8

    Use-after-free in Custom Highlight

    An attacker could have caused a use-after-free via the Custom Highlight API, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 135, Firefox ESR 115.20, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

  • Critical 9.8

    A bug in WebAssembly code generation could result in a crash

    A bug in WebAssembly code generation could have lead to a crash. It may have been possible for an attacker to leverage this to achieve code execution. This vulnerability was fixed in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

  • Critical 9.8

    Use-after-free during concurrent delazification

    A race during concurrent delazification could have led to a use-after-free. This vulnerability was fixed in Firefox 135, Firefox ESR 115.20, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

  • Critical 9.8

    Memory safety bugs fixed in Firefox 135, Thunderbird 135, Firefox ESR 115.20, Firefox ESR 128.7, Thunderbird 115.20, and Thunderbird 128.7

    Memory safety bugs present in Firefox 134, Thunderbird 134, Firefox ESR 115.19, Firefox ESR 128.6, Thunderbird 115.19, and Thunderbird 128.6. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could ha…

  • Critical 9.8

    Memory safety bugs fixed in Firefox 135, Thunderbird 135, Firefox ESR 128.7, and Thunderbird 128.7

    Memory safety bugs present in Firefox 134, Thunderbird 134, Firefox ESR 128.6, and Thunderbird 128.6. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.…

  • Critical 9.8

    Out-of-bounds access when resolving Promise objects

    An attacker was able to perform an out-of-bounds read or write on a JavaScript `Promise` object. This vulnerability was fixed in Firefox 138.0.4, Firefox ESR 128.10.1, Firefox ESR 115.23.1, Thunderbird 128.10.2, and Thunderbird 138.0.2.

  • Critical 9.8

    Use-after-free in FontFaceSet

    A use-after-free in FontFaceSet resulted in a potentially exploitable crash. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.

  • Critical 9.1

    Process isolation bypass using "javascript:" URI links in cross-origin frames

    A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended frame, potentially enabling a sandbox escape. This vulnerabil…

  • High 8.8

    Certificate length was not properly checked

    Certificate length was not properly checked when added to a certificate store. In practice only trusted data was processed. This vulnerability was fixed in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

  • High 8.8

    AudioIPC StreamData could trigger a use-after-free in the Browser process

    On Windows, a compromised content process could use bad StreamData sent over AudioIPC to trigger a use-after-free in the Browser process. This could have led to a sandbox escape. This vulnerability was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128…

  • High 8.8

    Out-of-bounds access when optimizing linear sums

    An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes. This vulnerability was fixed in Firefox 138.0.4, Firefox ESR 128.10.1, Firefox ESR 115.23.1, Thunderbird 128.10.2, and Thunderbird 138.0.2.

  • High 8.8

    No warning when opening executable terminal files on macOS

    The executable file warning did not warn users before opening files with the `terminal` extension. *This bug only affects Firefox for macOS. Other versions of Firefox are unaffected.*. This vulnerability was fixed in Firefox 140, Firefox ESR 128.12, Thunderbi…

  • High 8.1

    Inconsistent comparator in XSLT sorting led to out-of-bounds access

    An inconsistent comparator in xslt/txNodeSorter could have resulted in potentially exploitable out-of-bounds access. Only affected version 122 and later. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

  • High 8.1

    Memory safety bugs fixed in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9

    Memory safety bugs present in Firefox 136, Thunderbird 136, Firefox ESR 128.8, and Thunderbird 128.8. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.…

  • High 8.1

    JavaScript Execution via Spoofed PDF Attachment and file:/// Link

    Thunderbird's handling of the X-Mozilla-External-Attachment-URL header can be exploited to execute JavaScript in the file:/// context. By crafting a nested email attachment (message/rfc822) and setting its content type to application/pdf, Thunderbird may inco…

  • High 8.1

    Memory safety bugs fixed in Firefox 138, Thunderbird 138, Firefox ESR 128.10, and Thunderbird 128.10

    Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.…

  • High 8.1

    Memory safety bug fixed in Firefox ESR 128.10 and Thunderbird 128.10

    Memory safety bug present in Firefox ESR 128.9, and Thunderbird 128.9. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox ESR 128.1…

  • High 8.1

    Memory safety bugs fixed in Firefox 139, Thunderbird 139, Firefox ESR 128.11, and Thunderbird 128.11

    Memory safety bugs present in Firefox 138, Thunderbird 138, Firefox ESR 128.10, and Thunderbird 128.10. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary cod…

  • High 8.1

    Memory safety bug fixed in Firefox ESR 128.11 and Thunderbird 128.11

    Memory safety bug present in Firefox ESR 128.10, and Thunderbird 128.10. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox ESR 128…

  • High 7.8

    In resizeToAtLeast of SkRegion.cpp, there is a possible out of bounds write due to an integer overflow. This could lead…

  • High 7.6

    JIT corruption of WASM i32 return values on 64-bit CPUs

    On 64-bit CPUs, when the JIT compiles WASM i32 return values they can pick up bits from left over memory. This can potentially cause them to be treated as a different type. This vulnerability was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128.8, Th…

  • High 7.5

    Use-after-free in WebTransportChild

    It was possible to cause a use-after-free in the content process side of a WebTransport connection, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128.8, Thunderbird 136, and Thunderbir…

  • High 7.5

    Memory safety bugs fixed in Firefox 136, Thunderbird 136, Firefox ESR 115.21, Firefox ESR 128.8, and Thunderbird 128.8

    Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 115.20, Firefox ESR 128.7, and Thunderbird 128.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to…

  • High 7.5

    Sender Spoofing via Malformed From Header in Thunderbird

    Thunderbird parses addresses in a way that can allow sender spoofing in case the server allows an invalid From address to be used. For example, if the From header contains an (invalid) value "Spoofed Name ", Thunderbird treats spoofed@example.com as the actua…

  • High 7.3

    Adding %00 and a fake extension to a jar: URL changed the interpretation of the contents

    jar: URLs retrieve local file content packaged in a ZIP archive. The null and everything after it was ignored when retrieving the content from the archive, but the fake extension after the null was used to determine the type of content. This could have been u…

  • High 7.3

    URL Bar Spoofing via non-BMP Unicode characters

    A crafted URL containing specific Unicode characters could have hidden the true origin of the page, resulting in a potential spoofing attack. This vulnerability was fixed in Firefox 137, Firefox ESR 128.9, Thunderbird 137, and Thunderbird 128.9.

  • High 7.0

    Crafted email message incorrectly shown as being encrypted

    Certain crafted MIME email messages that claimed to contain an encrypted OpenPGP message, which instead contained an OpenPGP signed message, were wrongly shown as being encrypted. This vulnerability was fixed in Thunderbird 136 and Thunderbird 128.8.

  • Medium 6.5
    CVE-2025-0242 EPSS 15%

    Memory safety bugs fixed in Firefox 134, Thunderbird 134, Firefox ESR 115.19, Firefox ESR 128.6, Thunderbird 115.19, and Thunderbird 128.6

    Memory safety bugs present in Firefox 133, Thunderbird 133, Firefox ESR 115.18, Firefox ESR 128.5, Thunderbird 115.18, and Thunderbird 128.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could ha…

  • Medium 6.5

    Address of e-mail sender can be spoofed by malicious email

    Thunderbird displayed an incorrect sender address if the From field of an email used the invalid group name syntax that is described in CVE-2024-49040. This vulnerability was fixed in Thunderbird 128.7 and Thunderbird 135.

  • Medium 6.5

    Potential opening of private browsing tabs in normal browsing windows

    A race condition could have led to private browsing tabs being opened in normal browsing windows. This could have resulted in a potential privacy leak. This vulnerability was fixed in Firefox 135, Firefox ESR 128.7, Thunderbird 128.7, and Thunderbird 135.

  • Medium 6.5

    Unexpected GC during RegExp bailout processing

    It was possible to interrupt the processing of a RegExp bailout and run additional JavaScript, potentially triggering garbage collection when the engine was not expecting it. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and…

  • Medium 6.5

    Memory safety bugs fixed in Firefox 136, Thunderbird 136, Firefox ESR 128.8, and Thunderbird 128.8

    Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 128.7, and Thunderbird 128.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.…

  • Medium 6.5

    Use-after-free triggered by XSLTProcessor

    JavaScript code running while transforming a document with the XSLTProcessor could lead to a use-after-free. This vulnerability was fixed in Firefox 137, Firefox ESR 115.22, Firefox ESR 128.9, Thunderbird 137, and Thunderbird 128.9.

  • Medium 6.5

    Tracking Links in Attachments Bypassed Remote Content Blocking

    It was possible to craft an email that showed a tracking link as an attachment. If the user attempted to open the attachment, Thunderbird automatically accessed the link. The configuration to block remote content did not prevent that. Thunderbird has been fix…

  • Medium 6.5

    Unsolicited File Download, Disk Space Exhaustion, and Credential Leakage via mailbox:/// Links

    A crafted HTML email using mailbox:/// links can trigger automatic, unsolicited downloads of .pdf files to the user's desktop or home directory without prompting, even if auto-saving is disabled. This behavior can be abused to fill the disk with garbage data …

  • Medium 6.5

    Incorrect parsing of URLs could have allowed embedding of youtube.com

    Firefox could have incorrectly parsed a URL and rewritten it to the youtube.com domain when parsing the URL specified in an `embed` tag. This could have bypassed website security checks that restricted which domains users were allowed to embed. This vulnerabi…

  • Medium 6.4

    User Interface (UI) Misrepresentation of attachment URL

    When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL header, only the last link is shown when hovering over any attachment. Although the correct link is used on click, the misleading hover text could trick …

  • Medium 6.3

    Information Disclosure of /tmp directory listing

    By crafting a malformed file name for an attachment in a multipart message, an attacker can trick Thunderbird into including a directory listing of /tmp when the message is forwarded or edited as a new message. This vulnerability could allow attackers to disc…

  • Medium 6.3

    Leak of hashed Window credentials via crafted attachment URL

    Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be hosted externally. When an email is opened, Thunderbird accesses the specified URL to determine file size, and navigates to it when the user clicks the attac…

  • Medium 6.1

    Content-Disposition header ignored when a file is included in an embed or object tag

    When a file download is specified via the `Content-Disposition` header, that directive would be ignored if the file was included via a `<embed>` or `<object>` tag, potentially making a website vulnerable to a cross-site scripting attack. This vuln…

  • Medium 5.4
    CVE-2025-1015 Public exploit

    Unsanitized address book fields

    The Thunderbird Address Book URI fields contained unsanitized links. This could be used by an attacker to create and export an address book containing a malicious payload in a field. For example, in the “Other” field of the Instant Messaging section. If anoth…

  • Medium 5.4

    Clickjacking vulnerability could have led to leaking saved payment card details

    A clickjacking vulnerability could have been used to trick a user into leaking saved payment card details to a malicious page. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

  • Medium 5.3

    Use-after-free when breaking lines in text

    Assuming a controlled failed memory allocation, an attacker could have caused a use-after-free, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Firefox ESR 115.19, Thunderbird 134, and Thunderbird 12…

  • Medium 5.3

    Downloading of OpenPGP keys from WKD used incorrect padding

    When requesting an OpenPGP key from a WKD server, an incorrect padding size was used and a network observer could have learned the length of the requested email address. This vulnerability was fixed in Thunderbird 136 and Thunderbird 128.8.

  • Medium 4.8

    Unsafe attribute access during XPath parsing

    A vulnerability was identified in Thunderbird where XPath parsing could trigger undefined behavior due to missing null checks during attribute access. This could lead to out-of-bounds read access and potentially, memory corruption. This vulnerability was fixe…

  • Medium 4.8

    Potential local code execution in “Copy as cURL” command

    Due to insufficient escaping of the newline character in the “Copy as cURL” feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. This vulnerability was fixed in Firefox 139, Firefox…

  • Medium 4.8

    Potential local code execution in “Copy as cURL” command

    Due to insufficient escaping of the ampersand character in the “Copy as cURL” feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. *This bug only affects Firefox for Windows. Other …

  • Medium 4.3

    Clickjacking the registerProtocolHandler info-bar

    A web page could trick a user into setting that site as the default handler for a custom URL protocol. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

  • Medium 4.3

    Error handling for script execution was incorrectly isolated from web content

    Error handling for script execution was incorrectly isolated from web content, which could have allowed cross-origin leak attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 115.24, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

  • Medium 4.3

    Script element events leaked cross-origin resource status

    Script elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

  • Medium 4.3

    The WebCompat WebExtension shipped with Firefox exposed a persistent UUID

    An attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles. This vulnerability was fixed in Firefox 1…

References

  • report
    https://ubuntu.com/security/CVE-2024-43097
  • report
    https://ubuntu.com/security/CVE-2025-0238
  • report
    https://ubuntu.com/security/CVE-2025-0242
  • report
    https://ubuntu.com/security/CVE-2025-0510
  • report
    https://ubuntu.com/security/CVE-2025-1009
  • report
    https://ubuntu.com/security/CVE-2025-1010
  • report
    https://ubuntu.com/security/CVE-2025-1011
  • report
    https://ubuntu.com/security/CVE-2025-1012
  • report
    https://ubuntu.com/security/CVE-2025-1013
  • report
    https://ubuntu.com/security/CVE-2025-1014
  • report
    https://ubuntu.com/security/CVE-2025-1015
  • report
    https://ubuntu.com/security/CVE-2025-1016
  • report
    https://ubuntu.com/security/CVE-2025-1017
  • report
    https://ubuntu.com/security/CVE-2025-1930
  • report
    https://ubuntu.com/security/CVE-2025-1931
  • report
    https://ubuntu.com/security/CVE-2025-1932
  • report
    https://ubuntu.com/security/CVE-2025-1933
  • report
    https://ubuntu.com/security/CVE-2025-1934
  • report
    https://ubuntu.com/security/CVE-2025-1935
  • report
    https://ubuntu.com/security/CVE-2025-1936
  • report
    https://ubuntu.com/security/CVE-2025-1937
  • report
    https://ubuntu.com/security/CVE-2025-1938
  • report
    https://ubuntu.com/security/CVE-2025-2830
  • report
    https://ubuntu.com/security/CVE-2025-3028
  • report
    https://ubuntu.com/security/CVE-2025-3029
  • report
    https://ubuntu.com/security/CVE-2025-3030
  • report
    https://ubuntu.com/security/CVE-2025-3522
  • report
    https://ubuntu.com/security/CVE-2025-3523
  • report
    https://ubuntu.com/security/CVE-2025-3875
  • report
    https://ubuntu.com/security/CVE-2025-3909
  • report
    https://ubuntu.com/security/CVE-2025-3932
  • report
    https://ubuntu.com/security/CVE-2025-4083
  • report
    https://ubuntu.com/security/CVE-2025-4087
  • report
    https://ubuntu.com/security/CVE-2025-4091
  • report
    https://ubuntu.com/security/CVE-2025-4093
  • report
    https://ubuntu.com/security/CVE-2025-4918
  • report
    https://ubuntu.com/security/CVE-2025-4919
  • report
    https://ubuntu.com/security/CVE-2025-5263
  • report
    https://ubuntu.com/security/CVE-2025-5264