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.

Category

9.1
CVSS
Severity: Critical
CVSS 3.1 •
EPSS 0.02%
Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org
Affected: Mozilla Firefox
Affected: Mozilla Firefox ESR
Affected: Mozilla Thunderbird
Affected: Mozilla Thunderbird
Published at:
Updated at:

References

Link Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=1964767 permissions required
https://www.mozilla.org/security/advisories/mfsa2025-56/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-59/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-61/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2025-63/ vendor advisory

Frequently Asked Questions

What is the severity of CVE-2025-8037?
CVE-2025-8037 has been scored as a critical severity vulnerability.
How to fix CVE-2025-8037?
To fix CVE-2025-8037, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-8037 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-8037 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-8037?
CVE-2025-8037 affects Mozilla Firefox, Mozilla Firefox ESR, Mozilla Thunderbird, Mozilla Thunderbird.
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