CVE-2025-1936: firefox — Fix

Description

jar: URLs retrieve local file content packaged in a ZIP archive. The null and everything after it was ignored when retrieving the content from the archive, but the fake extension after the null was used to determine the type of content. This could have been used to hide code in a web extension disguised as something else like an image. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

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CVSS v3.1 Score

7.3

HIGH

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

Weakness Type (CWE)

CWE-158 CWE-158

Affected Products

Vendor	Product	Versions
mozilla	firefox	< 128.8.0
mozilla	firefox	< 136.0
mozilla	thunderbird	< 128.8.0
mozilla	thunderbird	129.0 — 136.0

References

Advisories & Patches

https://www.mozilla.org/security/advisories/mfsa2025-14/ 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=1940027 https://lists.debian.org/debian-lts-announce/2025/03/msg00006.html

Frequently Asked Questions

What is CVE-2025-1936? +

jar: URLs retrieve local file content packaged in a ZIP archive. The null and everything after it was ignored when retrieving the content from the archive, but the fake extension after the null was used to determine the type of content. This could have been used to hide code in a web extension disguised as something else like an image. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8. It has a CVSS v3.1 base score of 7.3 (HIGH).

How severe is CVE-2025-1936? +

CVE-2025-1936 has a CVSS v3.1 score of 7.3 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-1936? +

CVE-2025-1936 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-2025-1936? +

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.

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CVE-2025-1936