| Name | CVE-2020-26956 |
| Description | In 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. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| References | DLA-2457-1, DLA-2464-1, DSA-4793-1, DSA-4796-1 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| firefox (PTS) | sid | 138.0.4-1 | fixed |
| firefox-esr (PTS) | bullseye | 115.14.0esr-1~deb11u1 | fixed |
| bullseye (security) | 128.9.0esr-1~deb11u1 | fixed | |
| bookworm, bookworm (security) | 128.10.0esr-1~deb12u1 | fixed | |
| trixie | 128.10.0esr-1 | fixed | |
| sid | 128.10.1esr-1 | fixed | |
| thunderbird (PTS) | bullseye | 1:115.12.0-1~deb11u1 | fixed |
| bullseye (security) | 1:128.10.1esr-1~deb11u1 | fixed | |
| bookworm | 1:128.10.0esr-1~deb12u1 | fixed | |
| bookworm (security) | 1:128.10.1esr-1~deb12u1 | fixed | |
| trixie | 1:128.10.0esr-1 | fixed | |
| sid | 1:128.10.1esr-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| firefox | source | (unstable) | 83.0-1 | |||
| firefox-esr | source | stretch | 78.5.0esr-1~deb9u1 | DLA-2457-1 | ||
| firefox-esr | source | buster | 78.5.0esr-1~deb10u1 | DSA-4793-1 | ||
| firefox-esr | source | (unstable) | 78.5.0esr-1 | |||
| thunderbird | source | stretch | 1:78.5.0-1~deb9u1 | DLA-2464-1 | ||
| thunderbird | source | buster | 1:78.5.0-1~deb10u1 | DSA-4796-1 | ||
| thunderbird | source | (unstable) | 1:78.5.0-1 |
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