CVE-2026-100834 http4k before 6.48.0.0 Digest Authentication Replay Protection Bypass
Attackers can bypass Digest authentication replay protection in http4k by reusing captured credentials due to a default configuration flaw.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-100834?
CVE-2026-100834 is a high-severity vulnerability in http4k, published on 27 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-294
Which versions are affected by CVE-2026-100834?
6 open source packages ship an affected version, including org.http4k:http4k-security-digest.
| Package | Affected | Fixed in |
|---|---|---|
org.http4k:http4k-security-digest Maven | All versions | 4.51.0.0 |
org.http4k:http4k-security-digest Maven | All versions | 4.51.0.0 |
org.http4k:http4k-security-digest Maven | From 5.0.0.0 | 5.42.0.0 |
org.http4k:http4k-security-digest Maven | From 5.0.0.0 | 5.42.0.0 |
org.http4k:http4k-security-digest Maven | From 6.0.0.0 | 6.48.0.0 |
org.http4k:http4k-security-digest Maven | From 6.0.0.0 | 6.48.0.0 |
How do I fix CVE-2026-100834?
Upgrade org.http4k:http4k-security-digest to a fixed version for your release line: 4.51.0.0, 5.42.0.0 or 6.48.0.0.
Is CVE-2026-100834 being exploited?
There is no known exploitation of CVE-2026-100834 in the wild and no public exploit code.
Sources
Also known as GHSA-c7jm-38gq-h67h, GHSA-r39r-ww5m-7mv9.