CVE-2025-5263

MEDIUM 4.3CVE-2025-5263 · Published 27/05/2025 · updated 05/10/2026

In short

CVE-2025-5263 is a MEDIUM (CVSS 4.3) vulnerability affecting firefox (mozilla).
Chance of exploitation in the next 30 days (EPSS): 0.27%, higher than 18.6% of all vulnerabilities.
Fix: update to 128.11.0, 115.24.0, 139.0 or later.

Package	Affected versions	Patched versions
firefox mozilla	`≥ 116.0, < 128.11.0< 115.24.0< 139.0`	`128.11.0115.24.0139.0`

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.

References

bugzilla.mozilla.org/show_bug.cgi · Permissions Required
mozilla.org/security/advisories/mfsa2025-42 · Vendor Advisory
mozilla.org/security/advisories/mfsa2025-43 · Vendor Advisory
mozilla.org/security/advisories/mfsa2025-44 · Vendor Advisory
mozilla.org/security/advisories/mfsa2025-45
mozilla.org/security/advisories/mfsa2025-46
lists.debian.org/debian-lts-announce/2025/05/msg00043.html
lists.debian.org/debian-lts-announce/2025/05/msg00046.html

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Package

Affected versions

Patched versions

firefox

mozilla

≥ 116.0, < 128.11.0< 115.24.0< 139.0

128.11.0115.24.0139.0

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