CVE-2025-1933: firefox — Fix

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 was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

Is your site exposed to CVE-2025-1933?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.6

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

Affected Products

Vendor	Product	Versions
mozilla	firefox	< 115.21.0
mozilla	firefox	< 136.0
mozilla	firefox	116.0 — 128.8.0
mozilla	thunderbird	< 128.8
mozilla	thunderbird	129.0 — 136.0

References

Advisories & Patches

https://www.mozilla.org/security/advisories/mfsa2025-14/ https://www.mozilla.org/security/advisories/mfsa2025-15/ https://www.mozilla.org/security/advisories/mfsa2025-16/ https://www.mozilla.org/security/advisories/mfsa2025-17/ https://www.mozilla.org/security/advisories/mfsa2025-18/

Other References

https://bugzilla.mozilla.org/show_bug.cgi?id=1946004 https://lists.debian.org/debian-lts-announce/2025/03/msg00006.html

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.6 (HIGH).

How severe is CVE-2025-1933? +

CVE-2025-1933 has a CVSS v3.1 score of 7.6 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-1933? +

CVE-2025-1933 affects products from mozilla, specifically: firefox, thunderbird. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-1933? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2025-2857 10.0

Following the recent Chrome sandbox escape (CVE-2025-2783), various Firefox developers identified a similar pattern in our IPC code. A compromised …

CVE-2026-16367 10.0

Sandbox escape due to invalid pointer in the Disability Access APIs component. This vulnerability was fixed in Firefox 153 and …

CVE-2026-41512 9.9

ai-scanner is an AI model safety scanner built on NVIDIA garak. From version 1.0.0 to before version 1.4.1, there is …

CVE-2026-16408 9.8

Integer overflow in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CVE-2026-6768 9.8

Mitigation bypass in the Networking: Cookies component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

CVE-2026-16395 9.8

Integer overflow in the Audio/Video component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CVE-2025-1933