CVE-2021-29986
Mozilla: Race condition when resolving DNS names could have led to memory corruption
Severity
ImportantRed Hat Product Security
CVSS 3.0
Review impact separately from score.
Published · August 10, 2021
Updated · November 22, 2025
Description
A suspected race condition when calling getaddrinfo led to memory corruption and a potentially exploitable crash. Note: This issue only affected Linux operating systems. Other operating systems are unaffected. This vulnerability affects Thunderbird < 78.13, Thunderbird < 91, Firefox ESR < 78.13, and Firefox < 91.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.0 · 7.5CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition