CVE-2026-54478 (GCVE-0-2026-54478)
Vulnerability from cvelistv5
Published
2026-07-22 13:09
Modified
2026-07-22 14:14
CWE
  • CWE-290 - Authentication Bypass by Spoofing
Summary
In NLnet Labs Unbound 1.18.0 up to and including 1.25.1, when Unbound listens on a 'proxy-protocol-port' interface with 'answer-cookie: yes', the RFC 9018 server-cookie SipHash is computed over the proxy's wire address instead of the PROXYv2-declared client. One server cookie obtained through a given proxy node therefore validates for every PROXYv2-declared source behind that node. On a UDP+proxy-protocol front, an off-path attacker can harvest one cookie with a single legitimate query, then replay it under any spoofed source and pass DNS Cookie checks that were deployed to defeat this in the first place.
Impacted products
Vendor Product Version
NLnet Labs Unbound Version: 1.18.0   
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Show details on NVD website


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