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TI-2026-58181 Aliases CVE-2026-84639GHSA-4x6j-cpvp-7f2c

Uninitialized memory in MIME parsing

Priority MEDIUM 45CWE-457Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · None · High
Fix status
Partial Red Hat: 13 fixed, 3 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.

Summary

Triggering an error condition in certain MIME bodies would cause uninitialized memory to be used. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00323 25th percentileScored 2026-11-07
Fix Partial Thunderbird (Mozilla): 140.15, 153.2, 155Red Hat: 10 advisoriesRed Hat: 13 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

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

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaThunderbird—140.15, 153.2, 155Patch availableCNA
  • Thunderbird VendorMozilla Affected — Fixed in 140.15, 153.2, 155 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*before 140.15.0; 141.0 to before 153.2.0; 154.0 to before 155.0VulnerableMozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 140.15.0; 141.0 to before 153.2.0; 154.0 to before 155.0 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Thunderbird (Mozilla) Fixed in 140.15, 153.2, 155

Red Hat 10 advisories

  • RHSA-2026:82122 Released 2026-10-13 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.4) thunderbird-140.16.0-1.el8_4
    • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) thunderbird-140.16.0-1.el8_4
  • RHSA-2026:81912 Released 2026-10-13 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream E4S (v.8.8) thunderbird-140.16.0-1.el8_8
    • Red Hat Enterprise Linux AppStream TUS (v.8.8) thunderbird-140.16.0-1.el8_8
  • RHSA-2026:81913 Released 2026-10-13 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream AUS (v.8.6) thunderbird-140.16.0-1.el8_6
    • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) thunderbird-140.16.0-1.el8_6
Show 7 more Red Hat advisories
  • RHSA-2026:80503 Released 2026-10-12 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) thunderbird-140.15.0-1.el9_6
  • RHSA-2026:77632 Released 2026-10-08 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) thunderbird-140.15.0-1.el9_2
  • RHSA-2026:77627 Released 2026-10-08 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) thunderbird-140.15.0-1.el9_4
  • RHSA-2026:77631 Released 2026-10-08 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) thunderbird-140.15.0-1.el10_0
  • RHSA-2026:73971 Released 2026-09-30 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 8) thunderbird-140.16.0-1.el8_10
  • RHSA-2026:73130 Released 2026-09-29 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 10) thunderbird-140.16.0-1.el10_2
  • RHSA-2026:70642 Released 2026-09-24 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 9) thunderbird-140.16.0-1.el9_8

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-2026:73130
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:73971
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:70642
Red Hat Enterprise Linux AppStream AUS (v.8.4)Fixed RHSA-2026:82122
Red Hat Enterprise Linux AppStream AUS (v.8.6)Fixed RHSA-2026:81913
Red Hat Enterprise Linux AppStream E4S (v.8.8)Fixed RHSA-2026:81912
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:77632
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:77627
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:77631
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:80503
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4)Fixed RHSA-2026:82122
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6)Fixed RHSA-2026:81913
Red Hat Enterprise Linux AppStream TUS (v.8.8)Fixed RHSA-2026:81912

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-84639
  2. 2026-10-03 Alias added: GHSA-4x6j-cpvp-7f2c
  3. 2026-10-08 Fix available: Red Hat Enterprise Linux AppStream E4S (v.9.2), Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux AppStream EUS (v. 10.0) · Red Hat
  4. 2026-10-09 Fix available: RHSA-2026:77631 · Red Hat
  5. 2026-10-09 Fix available: RHSA-2026:77627 · Red Hat
  6. 2026-10-09 Fix available: RHSA-2026:77632 · Red Hat
  7. 2026-10-12 Fix available: RHSA-2026:80503 · Red Hat
  8. 2026-10-12 Fix available: Red Hat Enterprise Linux AppStream EUS (v.9.6) · Red Hat
  9. 2026-10-13 Fix available: RHSA-2026:81912 · Red Hat
  10. 2026-10-13 Fix available: RHSA-2026:81913 · Red Hat
  11. 2026-10-13 Fix available: Red Hat Enterprise Linux AppStream AUS (v.8.4), Red Hat Enterprise Linux AppStream AUS (v.8.6), Red Hat Enterprise Linux AppStream E4S (v.8.8) +3 · Red Hat
  12. 2026-10-14 Fix available: RHSA-2026:82122 · Red Hat

References

Advisory 3

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 2067 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences