CVE-2021-43535

HIGH

Firefox <93, Thunderbird <91.3, Firefox ESR <91.3 - Use After Free

Title source: llm
STIX 2.1

Description

A use-after-free could have occured when an HTTP2 session object was released on a different thread, leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 93, Thunderbird < 91.3, and Firefox ESR < 91.3.

References (8)

Core 8
Core References
Issue Tracking, Permissions Required, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/show_bug.cgi?id=1667102
Third Party Advisory vendor-advisory x_refsource_debian
https://www.debian.org/security/2021/dsa-5026
Mailing List, Third Party Advisory mailing-list x_refsource_mlist
https://lists.debian.org/debian-lts-announce/2021/12/msg00030.html
Issue Tracking, Third Party Advisory vendor-advisory x_refsource_debian
https://www.debian.org/security/2022/dsa-5034
Mailing List, Third Party Advisory mailing-list x_refsource_mlist
https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html

Scores

CVSS v3 8.8
EPSS 0.0119
EPSS Percentile 79.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Details

CWE
CWE-416
Status published
Products (6)
debian/debian_linux 9.0
debian/debian_linux 10.0
debian/debian_linux 11.0
mozilla/firefox < 93.0
mozilla/firefox_esr < 91.3.0
mozilla/thunderbird < 91.3.0
Published Dec 08, 2021
Tracked Since Feb 18, 2026