Vulnerability in Mozilla Firefox
CVE-2025-1933
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, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.
EPSS: 0.003 (21.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H.
Affected products
- Mozilla Firefox — versions 115.21, 128.8, 136
- Mozilla Thunderbird — versions 128.8, 136
Public proof-of-concept exploits
References
- security@mozilla.org (Issue Tracking)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- security@mozilla.org (Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2025-1933?
- CVE-2025-1933 is a high-severity vulnerability in Mozilla Firefox. CVSS score: 7.6/10. Published 2025-03-04.
- How severe is CVE-2025-1933?
- High severity. CVSS v3 base score is 7.6 out of 10.
- Is CVE-2025-1933 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.