CVE-2026-84642
Last modified
CVE-2026-84642 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. The values of the mail.allowed_attachment_hostnames advanced config setting were used in a regular expression without escaping. For some possible valid hostnames, this could allow certain unintended hostnames to also match and serve remote attachments. EPSS estimates a 0.27% chance of exploitation in the next 30 days.
Description
The values of the mail.allowed_attachment_hostnames advanced config setting were used in a regular expression without escaping. For some possible valid hostnames, this could allow certain unintended hostnames to also match and serve remote attachments. This vulnerability was fixed in Thunderbird 155 and Thunderbird 153.2.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Thunderbird | < 153.2.0 |
| Mozilla | Thunderbird | >= 154.0, < 155.0 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2060462Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-86/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-88/Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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