What is CVE-2026-57817?

CVE-2026-57817 is a high-severity vulnerability in Apache Cxf, classified under Improper Input Validation. CVSS score: 8.1/10. Published 2026-08-06.

How severe is CVE-2026-57817?

High severity. CVSS v3 base score is 8.1 out of 10.

Improper input validation in Apache Cxf

CVE-2026-57817

The OpenID Connect Core 1.0 specification mandates that the RP MUST validate the `c_hash` parameter when operating in the Hybrid Flow. If an Apache CXF RP is integrated with a non-compliant or misconfigured Identity Provider (IdP) that omits the `c_hash`, the RP becomes vulnerable to Authorization Code Substitution/Injection attacks. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2026-08-06 · last modified 2026-10-24.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (52.9th percentile), scored 2026-11-04.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 52.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Apache Cxf
Apache Software Foundation Cxf — versions 4.2.0, 4.0.0, 0

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

lists.apache.org/thread/pj63c3pf7kkp1xhr53do704fwj3t3htn (vendor-advisory, Mailing List, Vendor Advisory)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2026-57817?: CVE-2026-57817 is a high-severity vulnerability in Apache Cxf, classified under Improper Input Validation. CVSS score: 8.1/10. Published 2026-08-06.
How severe is CVE-2026-57817?: High severity. CVSS v3 base score is 8.1 out of 10.