CVE-2026-100834
Received Received - Intake

Digest Authentication Bypass in http4k Security Module

Publication date: 2026-09-27

Last updated on: 2026-09-27

Assigner: VulnCheck

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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-09-27
Last Modified
2026-09-27
Generated
2026-09-27
AI Q&A
2026-09-27
EPSS Evaluated
N/A
NVD
CVE-2026-100834
EUVD
EUVD-2026-87852

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
org.http4k http4k-security-digest to 4.51.0.0 (exc)
org.http4k http4k 6.48.0.0
org.http4k http4k 5.42.0.0
org.http4k http4k 4.51.0.0

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-294 A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability affects http4k's Digest authentication module (org.http4k:http4k-security-digest) in versions before 6.48.0.0, 5.42.0.0, and 4.51.0.0. The default nonceVerifier parameter is set to always return true, accepting any nonce regardless of value, age, or prior use. This disables replay protection, allowing attackers to reuse captured valid Digest authentication responses indefinitely.

Detection Guidance

To detect this vulnerability, check if your http4k application uses the Digest authentication module with default settings. Inspect the code for ServerFilters.DigestAuth or DigestAuthProvider without explicit nonceVerifier configuration. Look for versions below 6.48.0.0, 5.42.0.0, or 4.51.0.0. Monitor network traffic for repeated Digest authentication attempts using the same nonce.

Impact Analysis

If you use affected http4k versions, an attacker who captures a valid Digest authentication response could replay it to gain unauthorized access to protected resources. This could lead to data breaches, unauthorized actions, or persistent access to sensitive systems without needing to re-authenticate.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating confidentiality requirements in GDPR and HIPAA. Organizations using affected versions may fail compliance audits due to inadequate authentication replay protection, potentially resulting in legal penalties or data breach notifications.

Mitigation Strategies

Upgrade to patched versions 6.48.0.0, 5.42.0.0, or 4.51.0.0 immediately. If upgrading is not possible, explicitly configure a nonceVerifier that tracks issued nonces, enforces a TTL, and rejects reuse. Avoid relying on default settings for Digest authentication.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-100834. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart