CVE-2025-5263: firefox — Fix

Description

Error handling for script execution was incorrectly isolated from web content, which could have allowed cross-origin leak attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 115.24, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

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CVSS v3.1 Score

4.3

MEDIUM

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

Weakness Type (CWE)

CWE-346 CWE-346

Affected Products

Vendor	Product	Versions
mozilla	firefox	< 115.24.0
mozilla	firefox	< 139.0
mozilla	firefox	116.0 — 128.11.0

References

Advisories & Patches

https://www.mozilla.org/security/advisories/mfsa2025-42/ https://www.mozilla.org/security/advisories/mfsa2025-43/ https://www.mozilla.org/security/advisories/mfsa2025-44/

Other References

https://bugzilla.mozilla.org/show_bug.cgi?id=1960745 https://www.mozilla.org/security/advisories/mfsa2025-45/ https://www.mozilla.org/security/advisories/mfsa2025-46/ https://lists.debian.org/debian-lts-announce/2025/05/msg00043.html https://lists.debian.org/debian-lts-announce/2025/05/msg00046.html

Frequently Asked Questions

What is CVE-2025-5263? +

Error handling for script execution was incorrectly isolated from web content, which could have allowed cross-origin leak attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 115.24, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2025-5263? +

CVE-2025-5263 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-5263? +

CVE-2025-5263 affects products from mozilla, specifically: firefox. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-5263? +

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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