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TI-2026-81509 Aliases CVE-2026-118177GHSA-7w88-6r56-g2q9

Thunderbird calendar discovery accepts local file and share locations

Priority MEDIUM 46CWE-601Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Spoofing
Confidentiality · integrity · availability
High · None · High
Fix status
Partial Red Hat: 5 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-601.

Summary

Mozilla Thunderbird accepted calendar locations on other servers, local files or network shares during calendar discovery in a server directory. A malicious server, or a network attacker on plain HTTP lookups, can make Thunderbird subscribe to such a location. On Windows this leaks NTLM credentials to an attacker host on every calendar refresh, and calendar changes can be written to an attacker share or overwrite a local file.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

When looking for calendars in a directory on a server, during account setup or when adding a new network calendar, Thunderbird accepted calendar locations pointing to other servers, local files or network shares. A malicious server, or a network attacker when the lookup used plain HTTP, could make Thunderbird subscribe to such a location. On Windows this could leak the user's NTLM credentials to an attacker-controlled host on every calendar refresh, and changes to the calendar could be written to the attacker's share or overwrite a local file. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00452 39th percentileScored 2026-11-07
Fix Partial Thunderbird (Mozilla): 153.6, 159Red Hat: 5 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—153.6, 159Patch availableCNA
  • Thunderbird VendorMozilla Affected — Fixed in 153.6, 159 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*——Mozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions — — ·Mozilla

Remediation

Mozilla fixes this in Thunderbird 153.6 and Thunderbird 159. Red Hat lists Red Hat Enterprise Linux 6 and 7 as affected with no fix planned, and Red Hat Enterprise Linux 8, 9 and 10 as affected with no fix available.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA Thunderbird (Mozilla) Fixed in 153.6, 159

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 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-27 Threatist record created from CVE-2026-118177
  2. 2026-10-27 Fix available: Mozilla/[email protected] · CNA
  3. 2026-10-27 1 new reference · CNA
  4. 2026-10-27 Alias added: GHSA-7w88-6r56-g2q9
  5. 2026-10-29 Affected versions changed · Red Hat
  6. 2026-10-29 CVSS score added · Red Hat
  7. 2026-10-30 Affected versions changed · Red Hat
  8. 2026-10-30 CVSS score changed · Red Hat
  9. 2026-11-02 Affected versions changed · Red Hat
  10. 2026-11-04 CVSS score added · CISA ADP
  11. 2026-11-04 Weakness changed · CISA ADP
  12. 2026-11-04 CISA SSVC decision points changed
  13. 2026-11-04 Priority changed: LOW → MEDIUM
  14. 2026-11-06 Affected versions changed · Red Hat

References

Other 3

  • 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 4204 →

Sources

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