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TI-2021-10598 Aliases CVE-2021-29981GHSA-fxr9-2j9j-f89c

An issue present in lowering/register allocation could have led to obscure but…

Priority MEDIUM 40Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA.

Summary

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.

Why it matters now

EPSS 0.01012 63rd percentileScored 2026-11-07
Fix Fixed Firefox (Mozilla): 91Thunderbird (Mozilla): 91

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaFirefoxbefore 9191Patch availableCNA
MozillaThunderbirdbefore 9191Patch availableCNA
  • Firefox VendorMozilla Affected before 91 Fixed in 91 Patch available CNA
  • Thunderbird VendorMozilla Affected before 91 Fixed in 91 Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*before 91.0VulnerableMozilla
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*before 91.0VulnerableMozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 91.0 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 91.0 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Firefox (Mozilla) Fixed in 91
  • Fix · CNA Thunderbird (Mozilla) Fixed in 91

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Mozilla Firefox 91

    11 records Highest priority Priority MEDIUM 7 MEDIUM, 4 LOW

    Other records, highest priority first

    • TI-2021-10606 Out-of-bounds write in Mozilla ThunderbirdPriority MEDIUM 41
    • TI-2021-10605 Out-of-bounds read in Mozilla ThunderbirdPriority MEDIUM 41
    • TI-2021-10602 Use after free in Mozilla ThunderbirdPriority MEDIUM 41
    Show all 11 records →
  • Release ·

    Mozilla Thunderbird 91

    3 records Highest priority Priority MEDIUM 1 MEDIUM, 2 LOW

    Other records, highest priority first

    • TI-2021-10604 Missing brute-force protection in Mozilla FirefoxPriority LOW 31
    • TI-2021-10599 Due to incorrect JIT optimization, we incorrectly interpreted data from the wrong type of…Priority LOW 31
    Show all 3 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-29981
  2. 2026-10-03 Alias added: GHSA-fxr9-2j9j-f89c

References

Advisory 4

  • TI-2024-08981 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
  • TI-2019-08769 Improper input validation in Mozilla Firefox ESR KEVCVSS 3.1CRITICAL 10.0
  • TI-2010-03577 Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before… KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-04799 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
  • TI-2023-04477 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
See all 3444 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences