CVE-2021-29981

HIGH

Firefox < 91.0 - Deterministic Register Confusion in JIT Lowering

Title source: llm
STIX 2.1

Description

An issue present in lowering/register allocation could have led to obscure but deterministic register confusion failures in JITted code that would lead to a potentially exploitable crash. This vulnerability affects Firefox < 91 and Thunderbird < 91.

References (4)

Core 4
Core References
Issue Tracking, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/show_bug.cgi?id=1707774
Third Party Advisory vendor-advisory x_refsource_gentoo
https://security.gentoo.org/glsa/202202-03

Scores

CVSS v3 8.8
EPSS 0.0042
EPSS Percentile 61.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Details

Status published
Products (2)
mozilla/firefox < 91.0
mozilla/thunderbird < 91.0
Published Aug 17, 2021
Tracked Since Feb 18, 2026