CVE-2026-57817
Authorization code substitution in Apache CXF Hybrid Flow due to missing c_hash validation
Is CVE-2026-57817 being exploited?
Not confirmed. CVE-2026-57817 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.45% probability of exploitation in the next 30 days.
How severe is CVE-2026-57817?
CVE-2026-57817 is rated High with a CVSS score of 8.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-57817?
Yes. A fix has been recorded for CVE-2026-57817. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-57817 affect?
CVE-2026-57817 affects Apache CXF Relying Parties (versions prior to 4.2.3, 4.1.8, 3.6.12). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-57817?
Upgrade to Apache CXF 4.2.3 / 4.1.8 / 3.6.12 and validate IdP c_hash handling
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker can perform Authorization Code Substitution/Injection to obtain tokens or access victim sessions via a misconfigured/non-compliant IdP.
Patch when possible
- affected>= 4.2.0 and < 4.2.3
- affected>= 4.0.0 and < 4.1.8
- affected< 3.6.12
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.