by Kastro
Paper/Archive/CVE-2025-1942

CVE-2025-1942

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

EPSS 0.5%CVSS 9.8
critical.is priorityof 100
38
CVSS 9.8 (ADP)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 41.4.414 × 208.3No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Firefoxsee advisory136CNA
Thunderbirdsee advisory136CNA

Scores by source

CISA ADP9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refbugzilla.mozilla.org/show_bug.cgi?id=1947139refmozilla.org/security/advisories/mfsa2025-14refmozilla.org/security/advisories/mfsa2025-17