CVE-2026-12297

NameCVE-2026-12297
DescriptionSandbox escape due to incorrect boundary conditions in the Networking component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
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-4635-1, DLA-4636-1, DSA-6350-1, DSA-6351-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
firefox (PTS)sid152.0.1-1fixed
firefox-esr (PTS)bullseye115.14.0esr-1~deb11u1vulnerable
bullseye (security)140.12.0esr-1~deb11u1fixed
bookworm140.10.2esr-1~deb12u1vulnerable
bookworm (security)140.12.0esr-1~deb12u1fixed
trixie140.10.2esr-1~deb13u1vulnerable
trixie (security)140.12.0esr-1~deb13u1fixed
forky140.11.0esr-1vulnerable
sid140.12.0esr-1fixed
thunderbird (PTS)bullseye1:115.12.0-1~deb11u1vulnerable
bullseye (security)1:140.12.0esr-1~deb11u1fixed
bookworm1:140.10.1esr-1~deb12u1vulnerable
bookworm (security)1:140.12.0esr-1~deb12u1fixed
trixie1:140.10.1esr-1~deb13u1vulnerable
trixie (security)1:140.12.0esr-1~deb13u1fixed
forky1:140.11.0esr-1vulnerable
sid1:140.12.0esr-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
firefoxsource(unstable)152.0-1
firefox-esrsourcebullseye140.12.0esr-1~deb11u1DLA-4635-1
firefox-esrsourcebookworm140.12.0esr-1~deb12u1DLA-4635-1
firefox-esrsourcetrixie140.12.0esr-1~deb13u1DSA-6350-1
firefox-esrsource(unstable)140.12.0esr-1
thunderbirdsourcebullseye1:140.12.0esr-1~deb11u1DLA-4636-1
thunderbirdsourcebookworm1:140.12.0esr-1~deb12u1DLA-4636-1
thunderbirdsourcetrixie1:140.12.0esr-1~deb13u1DSA-6351-1
thunderbirdsource(unstable)1:140.12.0esr-1

Notes

https://www.mozilla.org/en-US/security/advisories/mfsa2026-57/#CVE-2026-12297
https://www.mozilla.org/en-US/security/advisories/mfsa2026-58/#CVE-2026-12297
https://www.mozilla.org/en-US/security/advisories/mfsa2026-61/#CVE-2026-12297

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