Summary
Multiple security issues were discovered in Firefox. If a user were
tricked into opening a specially crafted website, an attacker could
potentially exploit these to cause a denial of service, obtain sensitive
information across domains, or execute arbitrary code. (CVE-2025-1933,
CVE-2025-1934, CVE-2025-1935, CVE-2025-1936, CVE-2025-1937, CVE-2025-1942)
It was discovered that Firefox did not properly handle WebTransport
connection, leading to a use-after-free vulnerability. An attacker could
potentially exploit this issue to cause a denial of service.
(CVE-2025-1931)
Ivan Fratric discovered that Firefox did not properly handle XSLT sorting,
leading to a out-of-bounds access vulnerability. An attacker could
potentially exploit this issue to cause a denial of service, or execute
arbitrary code. (CVE-2025-1932)
Fixed packages 1
| Release | Package | Fixed in |
|---|---|---|
| Ubuntu · 20.04 LTS 20.04:LTS | firefox | 136.0+build3-0ubuntu0.20.04.1 |
Vulnerabilities 8
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Critical 9.8
Disclosure of uninitialized memory when .toUpperCase() causes string to get longer
When String.toUpperCase() caused a string to get longer it was possible for uninitialized memory to be incorporated into the result string. This vulnerability was fixed in Firefox 136 and Thunderbird 136.
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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.
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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…
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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…
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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…
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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…
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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…
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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.
References
-
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-2025-1942