CVE-2025-8036: Thunderbird cached CORS preflight responses across IP address changes
Source GCVE Database
Not known to be exploited · CVSS 8.1 High · fixed in 141 : patch affected systems soon.
Data as of 29 Oct 2026, 23:53 UTC
- Patch
- Available – fixed in 141, 140.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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
Weaponized: 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 29 Oct 2026.
What to do
AI-suggested
Mozilla has released official fixes for this vulnerability in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird ESR 140.1. Users and administrators should update affected products to these versions or later to remediate the issue. No additional mitigation steps are required beyond applying the official patches.
Description
A vulnerability in Thunderbird and Firefox allowed caching of CORS preflight responses across IP address changes, enabling circumvention of CORS protections via DNS rebinding attacks. This issue affects versions of Firefox prior to 141 and Firefox ESR prior to 140.1, as well as Thunderbird versions prior to 141 and 140.1. The vulnerability has been assigned CVE-2025-8036 and is rated with high severity. Mozilla has fixed this issue in Firefox 141 and Thunderbird 141.
References
- nvd.nist.gov/vuln/detail/CVE-2025-8036 (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=1960834 (opens in a new tab)
- kb.cert.org/vuls/id/652514 (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)