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.
Metrics
Affected Vendors & Products
Advisories
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Fixes
Solution
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References
History
Fri, 06 Nov 2026 22:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Bubka
Bubka 2fauth |
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| Vendors & Products |
Bubka
Bubka 2fauth |
Fri, 06 Nov 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | 2FAuth: Authenticated SSRF via DNS rebinding in the otpauth image= icon fetch (validate-then-fetch TOCTOU) | |
| Weaknesses | CWE-367 CWE-918 |
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| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-11-06T20:18:43.907Z
Reserved: 2026-07-16T19:35:57.767Z
Link: CVE-2026-63440
No data.
Status : Received
Published: 2026-11-06T21:17:10.137
Modified: 2026-11-06T21:17:10.137
Link: CVE-2026-63440
No data.
OpenCVE Enrichment
Updated: 2026-11-06T22:45:12Z