CVE-2026-84142
What it is
Internally found bugs present in Thunderbird 154. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 155 and Thunderbird 155.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.6% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Details
- Published
- Last modified
- Exploit probability
- 0.6% · EPSS, next 30 days
- Weakness
- CWE-119 · Buffer errors
- Record status
- Modified
Affected
- Mozilla Firefox < 155.0.0
- Mozilla Thunderbird < 155.0
Attack profile CVSS 3.1 · 9.8
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Fix and advisories
- https://www.mozilla.org/security/advisories/mfsa2026-82/
- https://www.mozilla.org/security/advisories/mfsa2026-86/
References
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=2029421%2C2040889%2C2045313%2C2045435%2C2053578%2C2058621%2C2058626
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=2048796%2C2053150%2C2057356
- https://www.mozilla.org/security/advisories/mfsa2026-82/
- https://www.mozilla.org/security/advisories/mfsa2026-86/