| Name | CVE-2020-26959 |
| Description | During 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. |
| 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 | 133.0.3-1 | fixed |
| firefox-esr (PTS) | jessie, jessie (lts) | 68.9.0esr-1~deb8u2 | vulnerable |
| stretch (security), stretch (lts), stretch | 91.11.0esr-1~deb9u1 | fixed | |
| buster (security), buster, buster (lts) | 115.12.0esr-1~deb10u1 | fixed | |
| bullseye | 115.14.0esr-1~deb11u1 | fixed | |
| bullseye (security) | 128.5.0esr-1~deb11u1 | fixed | |
| bookworm | 128.3.1esr-1~deb12u1 | fixed | |
| bookworm (security) | 128.5.0esr-1~deb12u1 | fixed | |
| trixie | 128.5.0esr-1 | fixed | |
| sid | 128.5.1esr-1 | fixed | |
| thunderbird (PTS) | jessie, jessie (lts) | 1:68.9.0-1~deb8u2 | vulnerable |
| stretch (security), stretch (lts), stretch | 1:91.10.0-1~deb9u1 | fixed | |
| buster (security), buster, buster (lts) | 1:115.12.0-1~deb10u1 | fixed | |
| bullseye | 1:115.12.0-1~deb11u1 | fixed | |
| bullseye (security) | 1:128.5.0esr-1~deb11u1 | fixed | |
| bookworm | 1:115.16.0esr-1~deb12u1 | fixed | |
| bookworm (security) | 1:128.5.0esr-1~deb12u1 | fixed | |
| sid, trixie | 1:128.5.2esr-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 | jessie | (unfixed) | end-of-life | ||
| 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 | jessie | (unfixed) | end-of-life | ||
| 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-2020-26959
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