CVE-2025-4093

NameCVE-2025-4093
DescriptionMemory 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 affects Firefox ESR < 128.10 and Thunderbird ESR < 128.10.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDSA-5910-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
firefox-esr (PTS)bullseye115.14.0esr-1~deb11u1vulnerable
bullseye (security)128.9.0esr-1~deb11u1vulnerable
bookworm128.8.0esr-1~deb12u1vulnerable
bookworm (security)128.10.0esr-1~deb12u1fixed
trixie128.9.0esr-2vulnerable
sid128.10.0esr-1fixed
thunderbird (PTS)bullseye1:115.12.0-1~deb11u1vulnerable
bullseye (security)1:128.10.0esr-1~deb11u1vulnerable
bookworm1:128.8.0esr-1~deb12u1vulnerable
bookworm (security)1:128.9.0esr-1~deb12u1vulnerable
trixie1:128.9.0esr-1vulnerable
sid1:128.10.0esr-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
firefox-esrsourcebookworm128.10.0esr-1~deb12u1DSA-5910-1
firefox-esrsource(unstable)128.10.0esr-1
thunderbirdsource(unstable)1:128.10.0esr-1

Notes

https://www.mozilla.org/en-US/security/advisories/mfsa2025-29/#CVE-2025-4093
https://www.mozilla.org/en-US/security/advisories/mfsa2025-32/#CVE-2025-4093

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