CVE-2025-8036: DNS rebinding circumvents CORS

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-07-22 · updated 2026-10-05
Weakness: CWE-350

Description

Thunderbird cached CORS preflight responses across IP address changes. This allowed circumventing CORS with DNS rebinding. This vulnerability was fixed in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird 140.1.

Affected products

Mozilla Firefox: before 140.1.0; before 141.0 — fixed in 140.1.0, 141.0
Mozilla Thunderbird: before 140.1.0; before 141.0 — fixed in 140.1.0, 141.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 140.1.0, 141.0; Mozilla Thunderbird 140.1.0, 141.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1960834
https://www.mozilla.org/security/advisories/mfsa2025-56/
https://www.mozilla.org/security/advisories/mfsa2025-59/
https://www.mozilla.org/security/advisories/mfsa2025-61/
https://www.mozilla.org/security/advisories/mfsa2025-63/
https://www.kb.cert.org/vuls/id/652514

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