CVE-2021-43535

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.

• CWE-416

• https://bugzilla.mozilla.org/show_bug.cgi?id=1667102Issue Tracking, Permissions Required, Vendor Advisory
• https://lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlMailing List, Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlMailing List, Third Party Advisory
• https://www.debian.org/security/2021/dsa-5026Third Party Advisory
• https://www.debian.org/security/2022/dsa-5034Issue Tracking, Third Party Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-43/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-49/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-50/Vendor Advisory
• https://bugzilla.mozilla.org/show_bug.cgi?id=1667102Issue Tracking, Permissions Required, Vendor Advisory
• https://lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlMailing List, Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlMailing List, Third Party Advisory
• https://www.debian.org/security/2021/dsa-5026Third Party Advisory
• https://www.debian.org/security/2022/dsa-5034Issue Tracking, Third Party Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-43/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-49/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-50/Vendor Advisory

Published

Dec 8, 2021

Last Modified

Jun 17, 2026

Status

Modified

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