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VulnerabilityPublished Updated

CVE-2026-34531: miguelgrinberg Flask-HTTPAuth · Improper Authentication

Affects miguelgrinberg Flask-HTTPAuthSource CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium : upgrade to 4.8.1 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
6.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 4.8.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade Flask-HTTPAuth and flask-httpauth to 4.8.1.

Affected software

ProductAffectedFixed in
miguelgrinbergFlask-HTTPAuthAffected
  • <4.8.1
Fixed in
  • 4.8.1
PyPIflask-httpauthpkg:pypi/flask-httpauthOther threatsAffected
  • <4.8.1
Fixed in
  • 4.8.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade Flask-HTTPAuth to version 4.8.1 or later, where this issue is patched. Applications should also ensure that no users have empty string tokens assigned. Patch status is confirmed fixed in version 4.8.1.

Description

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.

References

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