# CVE-2026-57817: Apache CXF: The authorization code hash (c_hash) is not enforced for the hybrid OIDC flow

> Attackers can bypass authentication in Apache CXF hybrid OIDC flows if the Identity Provider omits the c_hash parameter, allowing authorization code injection.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Aug 2026
- **Updated:** 7 Aug 2026
- **Also known as:** GHSA-h8f8-97w2-2925

## What is CVE-2026-57817?

CVE-2026-57817 is a high-severity authentication bypass vulnerability in Apache Cxf, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-57817?

It affects 1 product.


Products: Apache Cxf.

## How do I fix CVE-2026-57817?

Upgrade to a fixed version.

## Is CVE-2026-57817 being exploited?

There is no known exploitation of CVE-2026-57817 in the wild and no public exploit code.

## Other vulnerabilities in Apache Cxf

- [CVE-2012-2379](https://insights.sbomify.com/CVE-2012-2379/): XML Signature/Encryption Not Validated in Apache CXF (critical 10.0)
- [CVE-2026-66909](https://insights.sbomify.com/CVE-2026-66909/): Apache CXF: Unsafe deserialization of inbound JMS ObjectMessage (critical 9.8)
- [CVE-2026-68079](https://insights.sbomify.com/CVE-2026-68079/): Apache CXF: DefaultEncryptingCodeDataProvider allows unlimited authorization code replay (critical 9.8)
- [CVE-2026-50628](https://insights.sbomify.com/CVE-2026-50628/): Apache CXF: OAuth2: Inverted IP Binding Check Defeats Security Control (critical 9.8)
- [CVE-2025-48913](https://insights.sbomify.com/CVE-2025-48913/): Apache CXF: Untrusted JMS configuration can lead to RCE (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-57817 and fix it if it is affected.

What it is: CVE-2026-57817 is a high-severity authentication bypass vulnerability in Apache Cxf, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-57817 in the wild and no public exploit code.

Affected product: Apache Cxf. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-57817/ (Markdown: https://insights.sbomify.com/CVE-2026-57817/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-57817
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-57817
- OSV: https://osv.dev/vulnerability/CVE-2026-57817

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-57817/
Summaries are generated and may contain mistakes; the official description above is the record.