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, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
ReferencesDLA-2457-1, DLA-2464-1, DSA-4793-1, DSA-4796-1
NVD severitymedium

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
firefox (PTS)sid88.0.1-1fixed
firefox-esr (PTS)stretch68.10.0esr-1~deb9u1vulnerable
stretch (security)78.10.0esr-1~deb9u1fixed
buster78.8.0esr-1~deb10u1fixed
buster (security)78.10.0esr-1~deb10u1fixed
bullseye, sid78.10.0esr-1fixed
thunderbird (PTS)stretch1:68.10.0-1~deb9u1vulnerable
stretch (security)1:78.10.0-1~deb9u1fixed
buster1:78.6.0-1~deb10u1fixed
buster (security)1:78.10.0-1~deb10u1fixed
bullseye, sid1:78.10.0-1fixed

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-2020-26951
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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