{"id":"CVE-2025-1933","title":"On 64-bit CPUs, when the JIT compiles WASM i32 return values they can pick up bits from left over memory","summary":"On 64-bit CPUs, when the JIT compiles WASM i32 return values they can pick up bits from left over memory. This can potentially cause them to be treated as a different type. This vulnerability was fixed in Firefox 136, Firefox ESR 115.21,…","severity":"high","cvss":7.6,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H","vendor":"mozilla","product":"firefox","affected":["firefox < 115.21.0","firefox < 136.0","firefox >= 116.0, < 128.8.0","thunderbird < 128.8","thunderbird >= 129.0, < 136.0"],"patched":["firefox 128.8.0","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-2025-1933","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1946004","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-14/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-15/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-16/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-17/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-18/","label":"security@mozilla.org"},{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00006.html","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.00319,"epssPercentile":0.22439,"ingestedAt":"2026-09-30T19:21:07.227Z","slug":"CVE-2025-1933","body":"## Overview\n\nOn 64-bit CPUs, when the JIT compiles WASM i32 return values they can pick up bits from left over memory. This can potentially cause them to be treated as a different type. This vulnerability was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.\n\n## Affected\n\n- `firefox < 115.21.0`\n- `firefox < 136.0`\n- `firefox >= 116.0, < 128.8.0`\n- `thunderbird < 128.8`\n- `thunderbird >= 129.0, < 136.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `firefox 128.8.0`\n- `thunderbird 136.0`","depth":"twilight","depthScore":42,"depthScoreParts":{"impact":41.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}