How severe is CVE-2026-54147?

CVE-2026-54147 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-54147?

CVE-2026-54147 affects the following packages: org.http4k:http4k-security-digest (Maven), org.http4k:http4k-security-digest (Maven), org.http4k:http4k-security-digest (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-54147?

Update org.http4k:http4k-security-digest to 6.50.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54147 is resolved across your whole dependency graph.

How do I detect CVE-2026-54147 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.http4k:http4k-security-digest, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-54147 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-54147 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-54147 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-54147?

CVE-2026-54147 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 16th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-54147?

CVE-2026-54147 is classified as Broken Cryptographic Algorithm (CWE-327). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-54147 published, and has it been updated?

CVE-2026-54147 was published on September 18, 2026 and was last updated on September 26, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2026-54147 — http4k-security-digest

MEDIUMFix: http4k/http4k@65d23d9

CVE-2026-54147 is a medium-severity (CVSS 6.5) Broken Cryptographic Algorithm vulnerability in org.http4k:http4k-security-digest. A fix is available for org.http4k:http4k-security-digest — see the affected versions and patch details below.

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

Also known asGHSA-vxxm-wwqh-mh47

Published

Sep 18, 2026

Updated

Sep 26, 2026

Affected

3 pkgs

Patched

2 / 3

Exploits

None indexed

Exploitation data as of Oct 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-54147.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs16th percentile — riskier than 16% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-54147 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 382,205 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

3 pkgs affected

☕org.http4k:http4k-security-digest☕org.http4k:http4k-security-digest☕org.http4k:http4k-security-digest

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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).

Patches

Line	Fixed in	Edition
v6.x (Community)	6.50.0.0	Community
v5.x (LTS)	5.42.0.0	Enterprise — contact [email protected] (if Digest auth is present in your v5.x line)
v4.x (LTS)	4.51.0.0	Enterprise — contact [email protected] (if Digest auth is present in your v4.x line)

The fix:

Hashes with the configured algorithm instead of hardcoded MD5.

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

Affected Packages

3 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.http4k:http4k-security-digest`	≥ 6.0.0.0&&< 6.50.0.0	6.50.0.0`org.http4k:http4k-security-digest:6.50.0.0`
☕Maven	`org.http4k:http4k-security-digest`	≥ 5.0.0.0&&< 5.42.0.0	5.42.0.0`org.http4k:http4k-security-digest:5.42.0.0`
☕Maven	`org.http4k:http4k-security-digest`	all versions	No fix

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.http4k:http4k-security-digest, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.http4k:http4k-security-digest to 6.50.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54147 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact 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 `8a5