Authentication bypass via Digest header replay
Published Mar 12, 2026 · Updated Mar 12, 2026
Authentication bypass in Libsoup server-side Digest authentication allows remote attackers to access protected resources by replaying a captured header. The check_hex_urp validation recomputes the expected response but neither verifies that the server issued the nonce nor rejects a reused nonce-count value. Exploitation requires obtaining a legitimate user's Authorization header, after which identical requests can impersonate that user indefinitely.
Summary
What happened
Authentication bypass in Libsoup server-side Digest authentication allows remote attackers to access protected resources by replaying a captured header. The check_hex_urp validation recomputes the expected response but neither verifies that the server issued the nonce nor rejects a reused nonce-count value. Exploitation requires obtaining a legitimate user's Authorization header, after which identical requests can impersonate that user indefinitely.
The record
- CVE
- CVE-2026-3099
- Published
- Mar 12, 2026
- Updated
- Mar 12, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 10
- Classifications
- CWE-323, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 12, 2026CVE publishedPublication date reported by the CVE source.
- Mar 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GNOME Libsoup issue 495 replay reportproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo