CVE-2025-1942

Summary

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.

Impact & exploitability

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products we track (2)

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

Additional information

• NVD record
• https://www.mozilla.org/security/advisories/mfsa2025-14/Advisory
• https://www.mozilla.org/security/advisories/mfsa2025-17/Advisory
• https://bugzilla.mozilla.org/show_bug.cgi?id=1947139