CVE-2025-1933

Description

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 affects Firefox < 136, Firefox ESR < 115.21, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

7.6

CVSS

Severity: High

CVSS 3.1 •

EPSS 0.12%

Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org

Affected: Mozilla Firefox

Affected: Mozilla Firefox ESR

Affected: Mozilla Thunderbird

References

Link	Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=1946004	issue tracking
https://www.mozilla.org/security/advisories/mfsa2025-14/	vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-15/	vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-16/	vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-17/	vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-18/	vendor advisory

Frequently Asked Questions

What is the severity of CVE-2025-1933?: CVE-2025-1933 has been scored as a high severity vulnerability.
How to fix CVE-2025-1933?: To fix CVE-2025-1933, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-1933 being actively exploited in the wild?: As for now, there are no information to confirm that CVE-2025-1933 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-1933?: CVE-2025-1933 affects Mozilla Firefox, Mozilla Firefox ESR, Mozilla Firefox ESR, Mozilla Thunderbird, Mozilla Thunderbird.

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