CVE-2026-41569: authentik: WS-Federation wreply origin bypass can exfiltrate signed login responses to attacker-controlled endpoints
Vulnerability summary
CVE-2026-41569 is a medium (CVSS 6.9) URL Redirection to Untrusted Site vulnerability in goauthentik authentik. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7% of scored vulnerabilities.
Not severe (CVSS 6.9, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Timeline
- 02-06-2026PublishedVulnerability first disclosed.
- 03-06-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 2 sources · 2 versions- NVDNIST6.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS trend
Probability
0.18%
Chance of exploitation in the next 30 days
Percentile
7%
Versus all other CVEs
30-day change
Decrease -0.15 pp
From 0.32% on 04-10-2026
Known exploited
Compare KEV catalogsNot in the CISA KEV catalog.
Not in the ENISA CNW catalog.
Not in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Goauthentik1 product
- authentik< 2026.2.3
1 vendor · 1 product
References
1 links- github.com/goauthentik/authentik/security/advisories/GHSA-995q-72cw-cfw3X Refsource CONFIRMMitigationVendor Advisory