Apache CXF up to 3.6.11/4.1.7/4.2.2 c_hash input validation

Summaryinfo

A vulnerability was found in Apache CXF up to 3.6.11/4.1.7/4.2.2. It has been classified as critical. Impacted is an unknown function. This manipulation of the argument c_hash causes input validation. This vulnerability is registered as CVE-2026-57817. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability has been found in Apache CXF up to 3.6.11/4.1.7/4.2.2 and classified as critical. Affected by this vulnerability is an unknown code block. The manipulation of the argument c_hash with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at lists.apache.org. This vulnerability is known as CVE-2026-57817 since 06/25/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/06/2026).

Upgrading to version 3.6.12, 4.1.8 or 4.2.3 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Application Server Software

Vendor

• Apache

Name

• CXF

Version

• 3.6.0
• 3.6.1
• 3.6.2
• 3.6.3
• 3.6.4
• 3.6.5
• 3.6.6
• 3.6.7
• 3.6.8
• 3.6.9
• 3.6.10
• 3.6.11
• 4.1.0
• 4.1.1
• 4.1.2
• 4.1.3
• 4.1.4
• 4.1.5
• 4.1.6
• 4.1.7
• 4.2.0
• 4.2.1
• 4.2.2

License

• open-source

Website

• Vendor: https://www.apache.org/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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