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 was fixed in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird 140.1.
Published: 2025-07-22
Score: 9.1 Critical
EPSS: < 1% Very Low
KEV: No
Impact: Cookie hijacking / Authentication bypass
Action: Immediate Patch
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
EUVD EUVD EUVD-2025-22368 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.
Ubuntu USN Ubuntu USN USN-7991-1 Thunderbird vulnerabilities
History

Mon, 13 Apr 2026 15:00:00 +0000

Type Values Removed Values Added
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. 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 was fixed in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird 140.1.

Thu, 30 Oct 2025 16:15:00 +0000

Type Values Removed Values Added
Title firefox: thunderbird: Nameless cookies shadow secure cookies Nameless cookies shadow secure cookies

Tue, 29 Jul 2025 12:30:00 +0000

Type Values Removed Values Added
Title firefox: thunderbird: Nameless cookies shadow secure cookies
References
Metrics threat_severity

None

threat_severity

Moderate


Mon, 28 Jul 2025 19:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*

Wed, 23 Jul 2025 17:45:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Mozilla firefox Esr
Mozilla thunderbird
Vendors & Products Mozilla
Mozilla firefox
Mozilla firefox Esr
Mozilla thunderbird

Wed, 23 Jul 2025 15:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-614
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Tue, 22 Jul 2025 21:00:00 +0000

Type Values Removed Values Added
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.
References

Subscriptions

Mozilla Firefox Firefox Esr Thunderbird
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-04-13T14:26:53.773Z

Reserved: 2025-07-22T10:14:04.585Z

Link: CVE-2025-8037

cve-icon Vulnrichment

Updated: 2025-07-23T14:25:17.912Z

cve-icon NVD

Status : Modified

Published: 2025-07-22T21:15:50.860

Modified: 2026-04-13T15:17:10.840

Link: CVE-2025-8037

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-07-22T20:49:25Z

Links: CVE-2025-8037 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-20T20:15:06Z

Weaknesses