MEDIUM 5.9 NVD
CVE-2026-63440
2FAuth is a web app to manage Two-Factor Authentication (2FA) accounts and generate their security codes. Prior to 8.0.0, the otpauth image-fetch path validates
2FAuth is a web app to manage Two-Factor Authentication (2FA) accounts and generate their security codes. Prior to 8.0.0, the otpauth image-fetch path validates a hostname through ValidatesUrls::isExternalHost() and then lets IconService::storeRemoteImage() resolve the same hostname again for the HTTP request. When external otpauth image fetching is enabled, an authenticated user controlling low-TTL authoritative DNS can return a public address during validation and an internal address during the later connection, bypassing the private-address deny list to reach loopback, private-network, link-local, or cloud metadata endpoints. This issue is fixed in version 8.0.0.
References
- https://github.com/Bubka/2FAuth/commit/52e9db94f2da2a6231d77c49537d6d88ce948ee1
- https://github.com/Bubka/2FAuth/releases/tag/v8.0.0
- https://github.com/Bubka/2FAuth/security/advisories/GHSA-22mh-gmrh-gpwg
This medium severity vulnerability with a CVSS score of 5.9 was published on 2026-11-06 via NVD.
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