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TI-2021-16099 Aliases CVE-2021-38499GHSA-27c4-r36m-7cjh

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 92. 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 < 93.

Why it matters now

EPSS 0.00824 57th percentileScored 2026-11-07
Fix Fixed Firefox (Mozilla): 93

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaFirefoxbefore 9393Patch availableCNA
  • Firefox VendorMozilla Affected before 93 Fixed in 93 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*before 93.0VulnerableMozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 93.0 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Firefox (Mozilla) Fixed in 93

Fixed in the same release

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

  • Release ·

    Mozilla Firefox 93

    6 records Highest priority Priority MEDIUM 4 MEDIUM, 2 LOW

    Other records, highest priority first

    • TI-2021-16100 Mozilla developers reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1.Priority MEDIUM 41
    • TI-2021-16096 Use after free in Mozilla ThunderbirdPriority MEDIUM 41
    • TI-2021-16101 Mozilla developers reported memory safety bugs present in Firefox 92 and Firefox ESR 91.1.Priority MEDIUM 40
    Show all 6 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-38499
  2. 2026-10-03 Alias added: GHSA-27c4-r36m-7cjh

References

Advisory 1

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