RSS feed redirects Thunderbird subscription to local file or share
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · None · None
- 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-829.
Summary
Mozilla Thunderbird is affected. A remote RSS feed can set its stored subscription URL to a file: URL through the itunes:new-feed-url or newLocation element, a flaw caused by untrusted control of functionality (CWE-829). A malicious feed, or an attacker who can alter a feed delivered over HTTP, makes Thunderbird read local files on every update and, on Windows, connect to an attacker-controlled network share that can leak the user's NTLM credentials.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
Description from the CNA
A remote RSS feed could use the itunes:new-feed-url or newLocation element to permanently change its stored subscription URL to a file: URL. Thunderbird then read that location on every feed update. This allowed a malicious feed, or an attacker able to modify a feed delivered over HTTP, to make Thunderbird read local files and, on Windows, connect to an attacker-controlled network share, which could leak the user's NTLM credentials. The NTLM credential leak only affects Thunderbird on Windows. Other operating systems are affected by the local file read only. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Update Mozilla Thunderbird to 153.6 or 159. Red Hat plans no fix for Red Hat Enterprise Linux 6 and 7 and has no fix available yet for Red Hat Enterprise Linux 8, 9 and 10.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
- Fix · CNA Thunderbird (Mozilla) Fixed in 153.6, 159
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
Timeline
- 2026-10-27 Threatist record created from CVE-2026-118178
- 2026-10-27 Fix available: Mozilla/[email protected] · CNA
- 2026-10-27 1 new reference · CNA
- 2026-10-27 Alias added: GHSA-6j4v-p75m-p9wm
- 2026-11-04 CVSS score added · CISA ADP
- 2026-11-04 Weakness changed · CISA ADP
- 2026-11-04 CISA SSVC decision points changed
- 2026-11-05 Affected versions changed · Red Hat
- 2026-11-05 CVSS score added · Red Hat
References
More Mozilla vulnerabilities
- 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
Sources
- CVE-2026-118178 · CVE Program
- CVE-2026-118178 · NVD
- FIRST EPSS
- GHSA-6j4v-p75m-p9wm · GitHub Advisory Database · CC BY 4.0
- CVE-2026-118178 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences