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TI-2026-02380 Aliases CVE-2026-2776GHSA-v33x-35cm-8gjc

Memory corruption in Mozilla Firefox

Priority MEDIUM 50CWE-119Published · 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 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-119 and the CVSS impact.

Summary

Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00562 47th percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 115.33, 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
Yes
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—115.33, 140.8, 148Patch availableCNA
MozillaThunderbird—140.8, 148Patch availableCNA
  • Firefox VendorMozilla Affected — Fixed in 115.33, 140.8, 148 Patch available CNA
  • Thunderbird VendorMozilla Affected — Fixed in 140.8, 148 Patch available CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*before 115.33.0VulnerableMozilla
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*before 148.0VulnerableMozilla
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*128.0 to before 140.8.0VulnerableMozilla
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 115.33.0 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* Versions before 148.0 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* Versions 128.0 to before 140.8.0 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 115.33, 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-2026-2776
  2. 2026-10-03 Alias added: GHSA-v33x-35cm-8gjc
  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 5

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