VulnerabilityModified
CVE-2026-74989
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.
CRITICAL 9.8EPSS 0.33%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.33%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Internally found bugs present in Thunderbird 153. 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 154 and Thunderbird 154.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.33% probability · 26th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-119
- Affected
- mozilla/firefox · mozilla/thunderbird
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=2022257%2C2027351%2C2027380%2C2029289Not Applicable
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=2027388%2C2029750%2C2029794%2C2043298%2C2045126%2C2049810%2C2051741Not Applicable
- https://www.mozilla.org/security/advisories/mfsa2026-74/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-78/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.