{"id":"CVE-2025-1942","title":"When String.toUpperCase() caused a string to get longer it was possible for uninitialized memory to be incorporated into the result string","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.","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-908"],"vendor":"mozilla","product":"firefox","affected":["firefox < 136.0","thunderbird < 136.0"],"patched":["firefox 136.0","thunderbird 136.0"],"published":"2025-03-04","updated":"2026-09-30","sourceUpdated":"2026-09-30T19:10:01.007","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-1942","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1947139","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-14/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-17/","label":"security@mozilla.org"}],"tags":["nvd"],"epss":0.00479,"epssPercentile":0.38992,"ingestedAt":"2026-09-30T19:21:07.230Z","slug":"CVE-2025-1942","body":"## Overview\n\nWhen 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.\n\n## Affected\n\n- `firefox < 136.0`\n- `thunderbird < 136.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `firefox 136.0`\n- `thunderbird 136.0`","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}