CVE-2021-29976

HighCVSS 8.8/10Last modified Jun 17, 2026

Description

Mozilla developers reported memory safety bugs present in code shared between Firefox and Thunderbird. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Thunderbird < 78.12, Firefox ESR < 78.12, and Firefox < 90.

Metrics

CVSS 3.1 8.8/10CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Weakness enumeration

CWE-787

Affected software

Vendor	Product	Versions
Mozilla	Thunderbird	>= unspecified, < 78.12
Mozilla	Firefox ESR	>= unspecified, < 78.12
Mozilla	Firefox	>= unspecified, < 90

References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1700895%2C1703334%2C1706910%2C1711576%2C1714391Vendor Advisory
https://security.gentoo.org/glsa/202202-03Third Party Advisory
https://security.gentoo.org/glsa/202208-14Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2021-28/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-29/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-30/Vendor Advisory
https://bugzilla.mozilla.org/buglist.cgi?bug_id=1700895%2C1703334%2C1706910%2C1711576%2C1714391Vendor Advisory
https://security.gentoo.org/glsa/202202-03Third Party Advisory
https://security.gentoo.org/glsa/202208-14Third Party Advisory
https://www.mozilla.org/security/advisories/mfsa2021-28/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-29/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-30/Vendor Advisory

Timeline

Published: Aug 5, 2021
Last modified: Jun 17, 2026
NVD status: Modified

Related CVEs from 2021

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