CVE-2026-100834 (CVSS 5.9)

Description

http4k's Digest authentication module (org.http4k:http4k-security-digest) before versions 6.48.0.0, 5.42.0.0 and 4.51.0.0 defaults the nonceVerifier parameter of ServerFilters.DigestAuth and DigestAuthProvider to { true }, so every nonce is accepted regardless of its value, age, or prior use. Applications relying on this default have no replay protection on Digest authentication: an attacker who can capture a valid 'Authorization: Digest' response (for example by observing network traffic or reading logs) can replay it indefinitely against the same protected resource.

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CVSS v3.1 Score

5.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0032

Probability of exploitation

0.23%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-294 CWE-294

References

Other References

https://github.com/http4k/http4k/commit/4f904b4692 https://github.com/http4k/http4k/commit/8a52b615b1 https://github.com/http4k/http4k/security/advisories/GHSA-c7jm-38gq-h67h https://www.vulncheck.com/advisories/http4k-before-6.48.0.0-digest-authentication-replay-protection-bypass

Frequently Asked Questions

What is CVE-2026-100834? +

http4k's Digest authentication module (org.http4k:http4k-security-digest) before versions 6.48.0.0, 5.42.0.0 and 4.51.0.0 defaults the nonceVerifier parameter of ServerFilters.DigestAuth and DigestAuthProvider to { true }, so every nonce is accepted regardless of its value, age, or prior use. Applications relying on this default have no replay protection on Digest authentication: an attacker who can capture a valid 'Authorization: Digest' response (for example by observing network traffic or reading logs) can replay it indefinitely against the same protected resource. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2026-100834? +

CVE-2026-100834 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0032, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-100834? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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