🔐 CVE Alert

CVE-2025-1942

CRITICAL 9.8

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

CVSS Score
9.8
EPSS Score
0.0%
EPSS Percentile
0th

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.

Vendor mozilla
Product firefox
Ecosystems
Industries
Technology
Published Mar 4, 2025
Last Updated Apr 13, 2026
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Affected Versions

Mozilla / Firefox
All versions affected
Mozilla / Thunderbird
All versions affected

References

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

Credits

anbu