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TI-2026-02371 Aliases CVE-2026-2767GHSA-x8jx-9xwq-xwq6

Use after free in Mozilla Firefox

Priority MEDIUM 43CWE-416Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 17 fixed, 3 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00462 40th percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 140.8, 148Thunderbird (Mozilla): 140.8, 148Red Hat: 25 advisoriesRed Hat: 17 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaFirefox—140.8, 148Patch availableCNA
MozillaThunderbird—140.8, 148Patch availableCNA
  • Firefox VendorMozilla Affected — Fixed in 140.8, 148 Patch available CNA
  • Thunderbird VendorMozilla Affected — Fixed in 140.8, 148 Patch available CNA

CPE configurations NVD · 4

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*before 140.8.0VulnerableMozilla
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*before 148.0VulnerableMozilla
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*before 140.8.0VulnerableMozilla
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*before 148.0VulnerableMozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* Versions before 140.8.0 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* Versions before 148.0 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:* Versions before 140.8.0 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:* Versions before 148.0 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Firefox (Mozilla) Fixed in 140.8, 148
  • Fix · CNA Thunderbird (Mozilla) Fixed in 140.8, 148

Red Hat 25 advisories

  • RHSA-2026:4432 Released 2026-03-12 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream AUS (v. 8.2) thunderbird-140.8.0-1.el8_2
  • RHSA-2026:4260 Released 2026-03-11 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) thunderbird-140.8.0-2.el10_0
  • RHSA-2026:4152 Released 2026-03-10 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) firefox-140.8.0-2.el9_2, firefox-x11-140.8.0-2.el9_2
Show 22 more Red Hat advisories
  • RHSA-2026:3976 Released 2026-03-09 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) firefox-140.8.0-2.el10_0
  • RHSA-2026:4022 Released 2026-03-09 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream E4S (v.8.8) thunderbird-140.8.0-1.el8_8
    • Red Hat Enterprise Linux AppStream TUS (v.8.8) thunderbird-140.8.0-1.el8_8
  • RHSA-2026:3982 Released 2026-03-09 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) thunderbird-140.8.0-1.el9_6
  • RHSA-2026:3981 Released 2026-03-09 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v.9.4) thunderbird-140.8.0-1.el9_4
  • RHSA-2026:3984 Released 2026-03-09 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux Server (v. 7 ELS) firefox-140.8.0-2.el7_9
  • RHSA-2026:3980 Released 2026-03-09 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.4) thunderbird-140.8.0-2.el8_4
    • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) thunderbird-140.8.0-2.el8_4
  • RHSA-2026:3979 Released 2026-03-09 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.6) thunderbird-140.8.0-1.el8_6
    • Red Hat Enterprise Linux AppStream E4S (v.8.6) thunderbird-140.8.0-1.el8_6
    • Red Hat Enterprise Linux AppStream TUS (v.8.6) thunderbird-140.8.0-1.el8_6
  • RHSA-2026:3978 Released 2026-03-09 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) thunderbird-140.8.0-1.el9_2
  • RHSA-2026:3983 Released 2026-03-09 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.0) thunderbird-140.8.0-1.el9_0
  • RHSA-2026:3516 Released 2026-03-02 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 9) thunderbird-140.8.0-1.el9_7
  • RHSA-2026:3517 Released 2026-03-02 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 10) thunderbird-140.8.0-2.el10_1
  • RHSA-2026:3515 Released 2026-03-02 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 8) thunderbird-140.8.0-1.el8_10
  • RHSA-2026:3496 Released 2026-03-02 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v.9.4) firefox-140.8.0-2.el9_4, firefox-x11-140.8.0-2.el9_4
  • RHSA-2026:3497 Released 2026-03-02 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) firefox-140.8.0-2.el9_6, firefox-x11-140.8.0-2.el9_6
  • RHSA-2026:3495 Released 2026-03-02 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.6) firefox-140.8.0-2.el8_6
    • Red Hat Enterprise Linux AppStream E4S (v.8.6) firefox-140.8.0-2.el8_6
    • Red Hat Enterprise Linux AppStream TUS (v.8.6) firefox-140.8.0-2.el8_6
  • RHSA-2026:3494 Released 2026-03-02 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream E4S (v.8.8) firefox-140.8.0-2.el8_8
    • Red Hat Enterprise Linux AppStream TUS (v.8.8) firefox-140.8.0-2.el8_8
  • RHSA-2026:3493 Released 2026-03-02 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.0) firefox-140.8.0-2.el9_0
  • RHSA-2026:3492 Released 2026-03-02 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream AUS (v. 8.2) firefox-140.8.0-2.el8_2
  • RHSA-2026:3491 Released 2026-03-02 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.4) firefox-140.8.0-2.el8_4
    • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) firefox-140.8.0-2.el8_4
  • RHSA-2026:3361 Released 2026-02-25 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream (v. 10) firefox-140.8.0-2.el10_1
  • RHSA-2026:3339 Released 2026-02-25 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream (v. 9) firefox-140.8.0-2.el9_7, firefox-x11-140.8.0-2.el9_7
  • RHSA-2026:3338 Released 2026-02-25 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream (v. 8) firefox-140.8.0-2.el8_10

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:3361, RHSA-2026:3517
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:3338, RHSA-2026:3515
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:3339, RHSA-2026:3516
Red Hat Enterprise Linux AppStream AUS (v. 8.2)Fixed RHSA-2026:3492, RHSA-2026:4432
Red Hat Enterprise Linux AppStream AUS (v.8.4)Fixed RHSA-2026:3491, RHSA-2026:3980
Red Hat Enterprise Linux AppStream AUS (v.8.6)Fixed RHSA-2026:3495, RHSA-2026:3979
Red Hat Enterprise Linux AppStream E4S (v.8.6)Fixed RHSA-2026:3495, RHSA-2026:3979
Red Hat Enterprise Linux AppStream E4S (v.8.8)Fixed RHSA-2026:3494, RHSA-2026:4022
Red Hat Enterprise Linux AppStream E4S (v.9.0)Fixed RHSA-2026:3493, RHSA-2026:3983
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:3978, RHSA-2026:4152
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:3976, RHSA-2026:4260
Red Hat Enterprise Linux AppStream EUS (v.9.4)Fixed RHSA-2026:3496, RHSA-2026:3981
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:3497, RHSA-2026:3982
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4)Fixed RHSA-2026:3491, RHSA-2026:3980
Red Hat Enterprise Linux AppStream TUS (v.8.6)Fixed RHSA-2026:3495, RHSA-2026:3979
Red Hat Enterprise Linux AppStream TUS (v.8.8)Fixed RHSA-2026:3494, RHSA-2026:4022
Red Hat Enterprise Linux Server (v. 7 ELS)Fixed RHSA-2026:3984

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-2767
  2. 2026-10-03 Alias added: GHSA-x8jx-9xwq-xwq6
  3. 2026-10-23 EPSS moved to the 50th–90th percentile
  4. 2026-10-25 EPSS moved to the below the 50th percentile

References

Advisory 4

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