SB2023070638 - Input validation error in authentik

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Main Vulnerability Database SB2023070638

SB2023070638 - Input validation error in authentik

Published: July 6, 2023 Updated: April 23, 2026

Security Bulletin ID SB2023070638
CSH Severity
High
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

High 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Input validation error (CVE-ID: CVE-2023-36456)

The vulnerability allows a remote attacker to spoof IP addresses in logs, bypass IP-based policy checks, and influence IP-based controls in proxied applications.

The vulnerability exists due to improper input validation in X-Forwarded-For and X-Real-IP header handling in authentik when processing requests with user-supplied proxy IP headers. A remote attacker can send requests with crafted X-Forwarded-For or X-Real-IP headers to spoof IP addresses in logs, bypass IP-based policy checks, and influence IP-based controls in proxied applications.

Only deployments that are directly accessible by users without a reverse proxy are vulnerable.


Remediation

Install update from vendor's website.

References