CVE-2025-8037

Description

Setting a nameless cookie with an equals sign in the value shadowed other cookies. Even if the nameless cookie was set over HTTP and the shadowed cookie included the `Secure` attribute. This vulnerability affects Firefox < 141, Firefox ESR < 140.1, Thunderbird < 141, and Thunderbird < 140.1.

Reserved 2025-07-22 | Published 2025-07-22 | Updated 2025-07-22 | Assigner mozilla

Problem types

Nameless cookies shadow secure cookies

Product status

Any version before 141
affected

Any version before 140.1
affected

Any version before 141
affected

Any version before 140.1
affected

Credits

Uku Sõrmus

References

bugzilla.mozilla.org/show_bug.cgi?id=1964767

www.mozilla.org/security/advisories/mfsa2025-56/

www.mozilla.org/security/advisories/mfsa2025-59/

www.mozilla.org/security/advisories/mfsa2025-61/

www.mozilla.org/security/advisories/mfsa2025-63/

cve.org (CVE-2025-8037)

nvd.nist.gov (CVE-2025-8037)

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