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TI-2020-09944 Aliases CVE-2020-12426GHSA-jvpq-rx3j-c85r

Out-of-bounds write in Mozilla Firefox

Priority MEDIUM 41CWE-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 and community members reported memory safety bugs present in Firefox 77. 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 < 78.

Why it matters now

EPSS 0.01609 76th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed Firefox (Mozilla): 78

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaFirefoxbefore 7878Patch availableCNA
  • Firefox VendorMozilla Affected before 78 Fixed in 78 Patch available CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*before 78.0VulnerableMozilla
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*15.1VulnerableopenSUSE
cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*15.2VulnerableopenSUSE
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 78.0 Vulnerable ·Mozilla
  • cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:* Versions 15.1 Vulnerable ·openSUSE
  • cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:* Versions 15.2 Vulnerable ·openSUSE

Remediation

  • Fix · CNA Firefox (Mozilla) Fixed in 78

Fixed in the same release

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

  • Advisory ·

    Mozilla Firefox — openSUSE-SU-2020:0983

    13 records Highest priority Priority MEDIUM 6 MEDIUM, 7 LOW

    Other records, highest priority first

    • TI-2020-09937 Use after free in Mozilla Firefox ESRPriority MEDIUM 43
    • TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
    • TI-2020-09940 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 42
    Show all 13 records → Advisory →
  • Advisory ·

    Mozilla Firefox — openSUSE-SU-2020:1017

    13 records Highest priority Priority MEDIUM 6 MEDIUM, 7 LOW

    Other records, highest priority first

    • TI-2020-09937 Use after free in Mozilla Firefox ESRPriority MEDIUM 43
    • TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
    • TI-2020-09940 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 42
    Show all 13 records → Advisory →
Show 1 more group
  • Advisory ·

    Mozilla Firefox — GLSA-202007-10

    12 records Highest priority Priority MEDIUM 6 MEDIUM, 6 LOW

    Other records, highest priority first

    • TI-2020-09937 Use after free in Mozilla Firefox ESRPriority MEDIUM 43
    • TI-2020-09935 Reachable assertion in Mozilla Firefox ESRPriority MEDIUM 43
    • TI-2020-09940 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 42
    Show all 12 records → Advisory →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

Not affected: 4 products
  • Red Hat Enterprise Linux 5
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-12426
  2. 2026-10-03 Alias added: GHSA-jvpq-rx3j-c85r

References

Exploit 1

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