{"affected":[{"product":"2FAuth","source":"CNA: GitHub_M","vendor":"Bubka","versions":[{"status":"affected","version":"< 8.0.0"}]}],"cveId":"CVE-2026-63440","cwes":["CWE-367","CWE-918"],"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.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":5.9,"severity":"medium","source":"CNA: GitHub_M","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N","version":"3.1"}],"modifiedAt":1793996323907,"publishedAt":1793996323907,"references":[{"source":"CNA: GitHub_M","tags":["x_refsource_CONFIRM"],"url":"https://github.com/Bubka/2FAuth/security/advisories/GHSA-22mh-gmrh-gpwg"},{"source":"CNA: GitHub_M","tags":["x_refsource_MISC"],"url":"https://github.com/Bubka/2FAuth/commit/52e9db94f2da2a6231d77c49537d6d88ce948ee1"},{"source":"CNA: GitHub_M","tags":["x_refsource_MISC"],"url":"https://github.com/Bubka/2FAuth/releases/tag/v8.0.0"}],"remediation":[],"revision":"29b4ef466727b7745c1917b9bc51429a7929fb21977298ab86f241db17ad9eb6","sources":[{"modifiedAt":1793996323907,"name":"CNA: GitHub_M","retrievedAt":1793999373603,"url":"https://www.cve.org/CVERecord?id=CVE-2026-63440"}],"ssvc":null,"status":"published","title":"2FAuth: Authenticated SSRF via DNS rebinding in the otpauth image= icon fetch (validate-then-fetch TOCTOU)","updatedAt":1793999373603}