CVE-2020-26974

Name	CVE-2020-26974
Description	When flex-basis was used on a table wrapper, a StyleGenericFlexBasis object could have been incorrectly cast to the wrong type. This resulted in a heap user-after-free, memory corruption, and a potentially exploitable crash. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.
Source	CVE (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)
References	DLA-2496-1, DLA-2497-1, DSA-4813-1, DSA-4815-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
firefox (PTS)	sid	111.0.1-1	fixed
firefox-esr (PTS)	buster	91.12.0esr-1~deb10u1	fixed
	buster (security)	102.9.0esr-1~deb10u1	fixed
	bullseye	91.13.0esr-1~deb11u1	fixed
	bullseye (security)	102.9.0esr-1~deb11u1	fixed
	bookworm, sid	102.9.0esr-2	fixed
thunderbird (PTS)	buster	1:91.12.0-1~deb10u1	fixed
	buster (security)	1:102.9.0-1~deb10u1	fixed
	bullseye	1:91.13.0-1~deb11u1	fixed
	bullseye (security)	1:102.9.0-1~deb11u1	fixed
	bookworm	1:102.9.0-1	fixed
	sid	1:102.9.1-1	fixed

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

Package	Type	Release	Fixed Version	Origin
firefox	source	(unstable)	84.0-1
firefox-esr	source	stretch	78.6.0esr-1~deb9u1	DLA-2496-1
firefox-esr	source	buster	78.6.0esr-1~deb10u1	DSA-4813-1
firefox-esr	source	(unstable)	78.6.0esr-1
thunderbird	source	stretch	1:78.6.0-1~deb9u1	DLA-2497-1
thunderbird	source	buster	1:78.6.0-1~deb10u1	DSA-4815-1
thunderbird	source	(unstable)	1:78.6.0-1

Notes

https://www.mozilla.org/en-US/security/advisories/mfsa2020-54/#CVE-2020-26974
https://www.mozilla.org/en-US/security/advisories/mfsa2020-55/#CVE-2020-26974
https://www.mozilla.org/en-US/security/advisories/mfsa2020-56/#CVE-2020-26974