VulnerabilityModified
CVE-2025-1942
This vulnerability was fixed in Firefox 136 and Thunderbird 136.
CRITICAL 9.8EPSS 0.47%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.47%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
When String.toUpperCase() caused a string to get longer it was possible for uninitialized memory to be incorporated into the result string. This vulnerability was fixed in Firefox 136 and Thunderbird 136.
- 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
- 0.47% probability · 39th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-908
- Affected
- mozilla/firefox · mozilla/thunderbird
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1947139Issue Tracking
- https://www.mozilla.org/security/advisories/mfsa2025-14/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2025-17/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.