CVE-2025-5266

Published: May 27, 2025

Modified: Apr 13, 2026

PUBLISHED

Description

Script elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

Vendor	Product	Versions
Mozilla	Firefox	unaffected `128.11 - <= 128.` unaffected `139 - <= `
Mozilla	Thunderbird	unaffected `128.11 - <= 128.` unaffected `139 - <= `

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1965628

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

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

https://www.mozilla.org/security/advisories/mfsa2025-45/

https://www.mozilla.org/security/advisories/mfsa2025-46/

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CVE-2025-5266

Description

Affected Products

References