CVE-2020-26956

NameCVE-2020-26956
DescriptionIn some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, 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)sid113.0.2-1fixed
firefox-esr (PTS)buster91.12.0esr-1~deb10u1fixed
buster (security)102.11.0esr-1~deb10u1fixed
bullseye102.10.0esr-1~deb11u1fixed
bullseye (security)102.11.0esr-1~deb11u1fixed
bookworm, sid102.11.0esr-1fixed
thunderbird (PTS)buster1:91.12.0-1~deb10u1fixed
buster (security)1:102.11.0-1~deb10u1fixed
bullseye1:102.10.0-1~deb11u1fixed
bullseye (security)1:102.11.0-1~deb11u1fixed
bookworm, sid1:102.11.0-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
firefoxsource(unstable)83.0-1
firefox-esrsourcestretch78.5.0esr-1~deb9u1DLA-2457-1
firefox-esrsourcebuster78.5.0esr-1~deb10u1DSA-4793-1
firefox-esrsource(unstable)78.5.0esr-1
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-2020-26956
https://www.mozilla.org/en-US/security/advisories/mfsa2020-51/#CVE-2020-26956
https://www.mozilla.org/en-US/security/advisories/mfsa2020-52/#CVE-2020-26956

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