CVE-2020-26959

NameCVE-2020-26959
DescriptionDuring browser shutdown, reference decrementing could have occured on a previously freed object, resulting in a use-after-free, memory corruption, and a potentially exploitable crash. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-2457-1, DLA-2464-1, DSA-4793-1, DSA-4796-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
firefox (PTS)sid126.0-1fixed
firefox-esr (PTS)jessie, jessie (lts)68.9.0esr-1~deb8u2vulnerable
stretch (security), stretch (lts), stretch91.11.0esr-1~deb9u1fixed
buster91.12.0esr-1~deb10u1fixed
buster (security)115.11.0esr-1~deb10u1fixed
bullseye115.7.0esr-1~deb11u1fixed
bullseye (security)115.11.0esr-1~deb11u1fixed
bookworm115.7.0esr-1~deb12u1fixed
bookworm (security)115.11.0esr-1~deb12u1fixed
sid, trixie115.11.0esr-1fixed
thunderbird (PTS)jessie, jessie (lts)1:68.9.0-1~deb8u2vulnerable
stretch (security), stretch (lts), stretch1:91.10.0-1~deb9u1fixed
buster1:91.12.0-1~deb10u1fixed
buster (security)1:115.11.0-1~deb10u1fixed
bullseye1:115.7.0-1~deb11u1fixed
bullseye (security)1:115.11.0-1~deb11u1fixed
bookworm1:115.7.0-1~deb12u1fixed
bookworm (security)1:115.11.0-1~deb12u1fixed
trixie1:115.10.1-1fixed
sid1:115.11.0-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
firefoxsource(unstable)83.0-1
firefox-esrsourcejessie(unfixed)end-of-life
firefox-esrsourcestretch78.5.0esr-1~deb9u1DLA-2457-1
firefox-esrsourcebuster78.5.0esr-1~deb10u1DSA-4793-1
firefox-esrsource(unstable)78.5.0esr-1
thunderbirdsourcejessie(unfixed)end-of-life
thunderbirdsourcestretch1:78.5.0-1~deb9u1DLA-2464-1
thunderbirdsourcebuster1:78.5.0-1~deb10u1DSA-4796-1
thunderbirdsource(unstable)1:78.5.0-1

Notes

https://www.mozilla.org/en-US/security/advisories/mfsa2020-50/#CVE-2020-26959
https://www.mozilla.org/en-US/security/advisories/mfsa2020-51/#CVE-2020-26959
https://www.mozilla.org/en-US/security/advisories/mfsa2020-52/#CVE-2020-26959

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