CVE-2026-34531: medium-severity vulnerability in miguelgrinberg Flask-HTTPAuth
Flask-HTTPAuth invokes token verification callback when missing or empty token was given by client
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.5epss 0.3%
Flask-HTTPAuth provides Basic, Digest and Token HTTP authentication for Flask routes. Prior to version 4.8.1, in a situation where the client makes a request to a token protected resource without passing a token, or passing an empty token, Flask-HTTPAuth would invoke the application's token verification callback function with the token argument set to an empty string. If the application had any users in its database with an empty string set as their token, then it could potentially authenticate the client request against any of those users. This issue has been patched in version 4.8.1.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
Affected products
miguelgrinberg · Flask-HTTPAuthReferences
https://github.com/miguelgrinberg/flask-httpauth/commit/b15ffe9e50e110d7174ccd944f642079e1dcf9eehttps://github.com/miguelgrinberg/Flask-HTTPAuth/releases/tag/v4.8.1https://github.com/miguelgrinberg/Flask-HTTPAuth/security/advisories/GHSA-p44q-vqpr-4xmghttps://lists.debian.org/debian-lts-announce/2026/05/msg00049.html