CVE-2025-1942

Disclosure of uninitialized memory when .toUpperCase() causes string to get longer

CVSS 9.8 CRITICALEPSS 0.4%CWE-908

Vexday Risk Score

28Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 9.8EPSS 0.4%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

04 Mar 2025Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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

Affected products

Mozilla · Firefox Mozilla · Thunderbird

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References

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