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TI-2021-06309 Aliases CVE-2021-23988GHSA-jw26-3gw4-6p77

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 86. 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 < 87.

Why it matters now

EPSS 0.01076 65th percentileScored 2026-11-07
Fix Fixed Firefox (Mozilla): 87

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaFirefoxbefore 8787Patch availableCNA
  • Firefox VendorMozilla Affected before 87 Fixed in 87 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*before 87.0VulnerableMozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 87.0 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Firefox (Mozilla) Fixed in 87

Fixed in the same release

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

  • Release ·

    Mozilla Firefox 87

    8 records Highest priority Priority MEDIUM 2 MEDIUM, 6 LOW

    Other records, highest priority first

    • TI-2021-06308 Out-of-bounds write in Mozilla Firefox ESRPriority MEDIUM 41
    • TI-2021-06302 Out-of-bounds write in Mozilla Firefox ESRPriority LOW 38
    • TI-2021-06306 If an attacker is able to alter specific about:config values (for example malware running…Priority LOW 32
    Show all 8 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-23988
  2. 2026-10-03 Alias added: GHSA-jw26-3gw4-6p77

References

Advisory 2

  • 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