CVE-2026-8975

NameCVE-2026-8975
DescriptionMemory safety bugs present in Firefox ESR 115.35, Firefox ESR 140.10 and Firefox 150. 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. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-4592-1, DLA-4594-1, DSA-6283-1, DSA-6288-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
firefox (PTS)sid152.0.6-1fixed
firefox-esr (PTS)bullseye115.14.0esr-1~deb11u1vulnerable
bullseye (security)140.12.0esr-1~deb11u1fixed
bookworm, bookworm (security)140.12.0esr-1~deb12u1fixed
trixie (security), trixie140.12.0esr-1~deb13u1fixed
forky, sid140.12.0esr-1fixed
thunderbird (PTS)bullseye1:115.12.0-1~deb11u1vulnerable
bullseye (security)1:140.12.0esr-1~deb11u1fixed
bookworm, bookworm (security)1:140.12.0esr-1~deb12u1fixed
trixie (security), trixie1:140.12.0esr-1~deb13u1fixed
forky, sid1:140.12.0esr-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
firefoxsource(unstable)151.0-1
firefox-esrsourcebullseye140.11.0esr-1~deb11u1DLA-4592-1
firefox-esrsourcebookworm140.11.0esr-1~deb12u1DSA-6283-1
firefox-esrsourcetrixie140.11.0esr-1~deb13u1DSA-6283-1
firefox-esrsource(unstable)140.11.0esr-1
thunderbirdsourcebullseye1:140.11.0esr-1~deb11u1DLA-4594-1
thunderbirdsourcebookworm1:140.11.0esr-1~deb12u1DSA-6288-1
thunderbirdsourcetrixie1:140.11.0esr-1~deb13u1DSA-6288-1
thunderbirdsource(unstable)1:140.11.0esr-1

Notes

https://www.mozilla.org/en-US/security/advisories/mfsa2026-46/#CVE-2026-8975
https://www.mozilla.org/en-US/security/advisories/mfsa2026-48/#CVE-2026-8975
https://www.mozilla.org/en-US/security/advisories/mfsa2026-51/#CVE-2026-8975

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