CVE-2026-25748
authentik has a forward authentication bypass with broken cookie
7.5
HIGH
CVSS 3.1
EPSS 0.06%
Description
authentik is an open-source identity provider. Prior to 2025.10.4 and 2025.12.4, with a malformed cookie it was possible to bypass authentication when using forward authentication in the authentik Proxy Provider when used in conjunction with Traefik or Caddy as reverse proxy. When a malicious cookie was used, none of the authentik-specific X-Authentik-* headers were set which depending on application can grant access to an attacker. authentik 2025.10.4 and 2025.12.4 fix this issue.
How to fix CVE-2026-25748
To remediate CVE-2026-25748, upgrade the affected package to a fixed version below.
- —upgrade to 2025.12.4 or later
Is CVE-2026-25748 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- >= 2025.10.0, < 2025.12.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |