Read the docs
TI-2020-09940 Aliases CVE-2020-12422GHSA-7vm3-8xjm-5j9p

Out-of-bounds write in Mozilla Firefox

Priority MEDIUM 42CWE-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
Partial Red Hat: 9 fixed, 2 without a fix

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

Summary

In non-standard configurations, a JPEG image created by JavaScript could have caused an internal variable to overflow, resulting in an out of bounds write, memory corruption, and a potentially exploitable crash. This vulnerability affects Firefox < 78.

Why it matters now

EPSS 0.01938 80th percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 78Red Hat: 4 advisoriesRed Hat: 9 fixed, 2 without a fix

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

Red Hat 4 advisories

  • RHSA-2020:4080 Released 2020-09-30 · Red Hat rating Important
    firefox security and bug fix update
    • Red Hat Enterprise Linux Client (v. 7) firefox-78.3.0-1.el7_9
    • Red Hat Enterprise Linux Client Optional (v. 7) firefox-78.3.0-1.el7_9
    • Red Hat Enterprise Linux Server (v. 7) firefox-78.3.0-1.el7_9
    • Red Hat Enterprise Linux Server Optional (v. 7) firefox-78.3.0-1.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) firefox-78.3.0-1.el7_9
    • Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-78.3.0-1.el7_9
  • RHSA-2020:3559 Released 2020-08-26 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox-78.2.0-3.el8_1
  • RHSA-2020:3557 Released 2020-08-26 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream (v. 8) firefox-78.2.0-2.el8_2
Show 1 more Red Hat advisories
  • RHSA-2020:3555 Released 2020-08-26 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox-78.2.0-3.el8_0

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-2020-09938 Race condition in Mozilla Firefox ESRPriority 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-2020-09938 Race condition in Mozilla Firefox ESRPriority 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-2020-09938 Race condition in Mozilla Firefox ESRPriority MEDIUM 42
    Show all 12 records → Advisory →

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 5AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2020:3557
Red Hat Enterprise Linux AppStream E4S (v. 8.0)Fixed RHSA-2020:3555
Red Hat Enterprise Linux AppStream EUS (v. 8.1)Fixed RHSA-2020:3559
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2020:4080
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2020:4080
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2020:4080
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2020:4080
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2020:4080
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2020:4080

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-12422
  2. 2026-10-03 Alias added: GHSA-7vm3-8xjm-5j9p

References

Advisory 5

  • 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