CVE-2026-41569Network attack vector

Signed login response theft via prefix validation

Published Jun 2, 2026 · Updated Jun 2, 2026

Open redirect in authentik before 2026.2.3 allows remote attackers to steal signed WS-Federation login responses through crafted links. The WS-Federation sign-in processor accepts wreply values whose raw strings merely start with the configured Reply URL, then uses the supplied URL as the browser's autosubmit destination. Exploitation requires an enterprise WS-Federation provider with a prefix-ambiguous Reply URL and victim interaction; replayable responses enable impersonation in the relying application.

CVSS severity6.9
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in authentik before 2026.2.3 allows remote attackers to steal signed WS-Federation login responses through crafted links. The WS-Federation sign-in processor accepts wreply values whose raw strings merely start with the configured Reply URL, then uses the supplied URL as the browser's autosubmit destination. Exploitation requires an enterprise WS-Federation provider with a prefix-ambiguous Reply URL and victim interaction; replayable responses enable impersonation in the relying application.

The record

CVE
CVE-2026-41569
Published
Jun 2, 2026
Updated
Jun 2, 2026
Vendor
Authentik Security Inc.
Product
authentik
Classifications
CWE-601, T1566.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2026.2.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Authentik Security Inc. · authentikversion=< 2026.2.3

Published CVSS scores

6.1NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.9GitHub, Inc.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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')
T1566.002Spearphishing Link

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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