CVE-2020-26951

NameCVE-2020-26951
DescriptionA parsing and event loading mismatch in Firefox's SVG code could have allowed load events to fire, even after sanitization. An attacker already capable of exploiting an XSS vulnerability in privileged internal pages could have used this attack to bypass our built-in sanitizer. 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)sid133.0-1fixed
firefox-esr (PTS)jessie, jessie (lts)68.9.0esr-1~deb8u2vulnerable
stretch (security), stretch (lts), stretch91.11.0esr-1~deb9u1fixed
buster (security), buster, buster (lts)115.12.0esr-1~deb10u1fixed
bullseye115.14.0esr-1~deb11u1fixed
bullseye (security)128.5.0esr-1~deb11u1fixed
bookworm128.3.1esr-1~deb12u1fixed
bookworm (security)128.5.0esr-1~deb12u1fixed
sid, trixie128.5.0esr-1fixed
thunderbird (PTS)jessie, jessie (lts)1:68.9.0-1~deb8u2vulnerable
stretch (security), stretch (lts), stretch1:91.10.0-1~deb9u1fixed
buster (security), buster, buster (lts)1:115.12.0-1~deb10u1fixed
bullseye1:115.12.0-1~deb11u1fixed
bullseye (security)1:128.5.0esr-1~deb11u1fixed
bookworm1:115.16.0esr-1~deb12u1fixed
bookworm (security)1:128.5.0esr-1~deb12u1fixed
sid, trixie1:128.5.0esr-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-2020-26951
https://www.mozilla.org/en-US/security/advisories/mfsa2020-51/#CVE-2020-26951
https://www.mozilla.org/en-US/security/advisories/mfsa2020-52/#CVE-2020-26951

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