CVE-2025-8037: Mozilla Firefox · Vulnerability
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 9.1 Critical : upgrade to 141 as a priority.
Data as of 26 Oct 2026, 07:57 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 141
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 22 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
Upgrade Mozilla Firefox to 141.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mozilla Firefox | Affected
| Fixed in
|
AI-suggested
Mozilla has released official fixes for this vulnerability in Firefox 141 and Firefox ESR 140.1. Users and administrators should update affected Firefox installations to version 141 or later, or Firefox ESR 140.1 or later, to remediate this issue. Patch status is confirmed by multiple Mozilla security advisories. No additional mitigation steps are required beyond applying the official updates.
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.
References
- bugzilla.mozilla.org/show_bug.cgi?id=1964767 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-56/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-59/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-61/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-63/ (opens in a new tab)