CVE-2026-57817

Apache CXF: The authorization code hash (c_hash) is not enforced for the hybrid OIDC flow

HIGH
8.1
CVSS Score
Published: August 6, 2026 at 10:24 AM UTC
Updated: October 24, 2026 at 04:10 PM UTC
1 product affected across 1 vendorCXF

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Severity
HIGH8.1
Exploit prediction
EPSS 0.7%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

95%
v < 3.6.124.0.0 ≤ v < 4.1.84.2.0 ≤ v < 4.2.34.0.04.2.0
Affected range stops below 3.6.12, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.1.8, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.2.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

Vendor AdvisoryMailing List
Source: cverecord
https://lists.apache.org/thread/pj63c3pf7kkp1xhr53do704fwj3t3htn
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2026/08/06/19

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHCISA-ADP
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-20

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