Vulnerability in Http4k

CVE-2026-54147

http4k is a functional toolkit for Kotlin HTTP applications. Prior to 4.51.0.0, 5.42.0.0, and 6.50.0.0, DigestAuthProvider.verify in http4k-security-digest ignores its configured algorithm parameter and verifies every Digest response with hardcoded MD5. Deployments configured for SHA-256 therefore receive weaker MD5-based verification, exposing Digest authentication to collision-related attack paths that depend on the hash function's collision resistance. This issue is fixed in versions 4.51.0.0, 5.42.0.0, and 6.50.0.0.

Vulnerability class: POODLE (CVE-2014-3566)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N.

EPSS exploit prediction

EPSS: 0.003 (17.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 17th percentile — 17.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-54147: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

  • Http4k — versions < 4.51.0.0, >= 5.0.0.0, < 5.42.0.0, >= 6.0.0.0, < 6.50.0.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-54147?
CVE-2026-54147 is a medium-severity vulnerability in Http4k, classified under Use of a Broken or Risky Cryptographic Algorithm. CVSS score: 6.5/10. Published 2026-09-18.
How severe is CVE-2026-54147?
Medium severity. CVSS v3 base score is 6.5 out of 10.