High severity · published Aug 6, 2026
CVE-2026-57817
Apache CXF: The authorization code hash (c_hash) is not enforced for the hybrid OIDC flow
8.1
CVSS
0.7%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 53% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AC
Apache CXF · Apache Software Foundation
4.2.0 before 4.2.3; 4.0.0 before 4.1.8; before 3.6.12 · source: vendor
CX
Cxf · Apache
before 3.6.12; 4.0.0 before 4.1.8; 4.2.0 before 4.2.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-57817
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-57817
Mailing List
https://lists.apache.org/thread/pj63c3pf7kkp1xhr53do704fwj3t3htn
www.openwall.com
http://www.openwall.com/lists/oss-security/2026/08/06/19
More from Apache CXF
9.8
CVE-2026-68079
Apache CXF: DefaultEncryptingCodeDataProvider allows unlimited authorization code replay
9.8
CVE-2026-66909
Apache CXF: Unsafe deserialization of inbound JMS ObjectMessage
9.8
CVE-2026-50628
Apache CXF: OAuth2: Inverted IP Binding Check Defeats Security Control
9.8
CVE-2026-49875
Apache CXF: XML External Entity (XXE) Injection in W3CMultiSchemaFactory and EndpointReferenceUtils
9.8
CVE-2026-44930
Apache CXF: LDAP Injection vulnerability in XKMS LDAP Repository