CVE-2026-54147

http4k: DigestAuthProvider.verify ignored configured algorithm and did not bind to request URI

Workarounds

For deployments that cannot upgrade immediately:

• Algorithm gap: do not rely on algorithm configuration; assume MD5 is in use and treat the Digest credentials as low-trust.

References

• Vulnerability first present: 8a52b615b1
• Algorithm fix: 65d23d99fc
• Fix release: v6.50.0.0
• Background: RFC 7616, HTTP Digest Access Authentication

An issue in DigestAuthProvider.verify:

Algorithm silently forced to MD5. The configured algorithm parameter was ignored, every verification used MD5 regardless of configuration. Deployments believing they were running SHA-256 Digest auth were silently inheriting MD5's collision weaknesses, including documented attack paths against Digest schemes that rely on the hash being collision-resistant.

Who is affected: any application using http4k-security-digest for HTTP Digest authentication. The bug has been present since DigestAuthProvider was introduced (commit 8a52b615b1, 2021).

The application uses a cryptographic algorithm known to have weaknesses, such as MD5, SHA-1, or DES. Typical impact: compromised confidentiality or integrity of protected data.

CVE-2026-54147 has a CVSS score of 6.5 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.42.0.0, 6.50.0.0); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

The fix:

• Hashes with the configured algorithm instead of hardcoded MD5.

1. What is CVE-2026-54147? CVE-2026-54147 is a medium-severity use of a broken or risky cryptographic algorithm vulnerability in org.http4k:http4k-security-digest (maven), affecting versions >= 5.0.0.0, < 5.42.0.0. It is fixed in 5.42.0.0, 6.50.0.0. The application uses a cryptographic algorithm known to have weaknesses, such as MD5, SHA-1, or DES.
2. How severe is CVE-2026-54147? CVE-2026-54147 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of org.http4k:http4k-security-digest are affected by CVE-2026-54147? org.http4k:http4k-security-digest (maven) versions >= 5.0.0.0, < 5.42.0.0 is affected.
4. Is there a fix for CVE-2026-54147? Yes. CVE-2026-54147 is fixed in 5.42.0.0, 6.50.0.0. Upgrade to this version or later.
5. Is CVE-2026-54147 exploitable, and should I be worried? Whether CVE-2026-54147 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-54147 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-54147?
   • Upgrade org.http4k:http4k-security-digest to 5.42.0.0 or later
   • Upgrade org.http4k:http4k-security-digest to 6.50.0.0 or later