Read the docs
TI-2021-10583 Aliases CVE-2021-29966GHSA-p2f5-76jq-f5vv

Out-of-bounds write in Mozilla Firefox

Priority MEDIUM 40CWE-787Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-787 and the CVSS impact.

Summary

Mozilla developers reported memory safety bugs present in Firefox 88. 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 Firefox < 89.

Why it matters now

EPSS 0.01022 63rd percentileScored 2026-11-07
Fix Fixed Firefox (Mozilla): 89

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaFirefoxbefore 8989Patch availableCNA
  • Firefox VendorMozilla Affected before 89 Fixed in 89 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*78.11.0 to before 89.0VulnerableMozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions 78.11.0 to before 89.0 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Firefox (Mozilla) Fixed in 89

Fixed in the same release

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

  • Advisory ·

    Mozilla Firefox — GLSA-202107-09

    4 records Highest priority Priority MEDIUM 1 MEDIUM, 3 LOW

    Other records, highest priority first

    • TI-2021-10577 Firefox used to cache the last filename used for printing a file.Priority LOW 22
    • TI-2021-10576 Incorrect authorization in Mozilla FirefoxPriority LOW 22
    • TI-2021-10578 Incorrect authorization in Mozilla FirefoxPriority LOW 21
    Show all 4 records → Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-29966
  2. 2026-10-03 Alias added: GHSA-p2f5-76jq-f5vv

References

Advisory 2

Other 1

  • 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