Open Redirect in Apache Software Foundation Syncope

CVE-2026-73191

URL Redirection to Untrusted Site ('Open Redirect') vulnerability in Apache Syncope. When the Syncope SRA is configured for CAS authentication, the target Apereo CAS instance's URL is calculated by unconditionally looking at client-supplied forwarded HTTP headers. This issue affects Apache Syncope: from 3.0.0-M0 through 3.0.16, from 4.0.0-M0 Through 4.0.7, from 4.1.0-M0 through 4.1.2. Users are recommended to upgrade to version 4.0.8 / 4.1.3, which fix this issue.

Vulnerability class: Open Redirect

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (23.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-73191: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-73191?
CVE-2026-73191 is a medium-severity vulnerability in Apache Software Foundation Syncope, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2026-09-14.
How severe is CVE-2026-73191?
Medium severity. CVSS v3 base score is 6.1 out of 10.