CVE-2026-54478

Published: Lug 22, 2026 Last Modified: Lug 24, 2026
ExploitDB:
Other exploit source:
Google Dorks:
LOW 3,7
Source: [email protected]
Attack Vector: network
Attack Complexity: high
Privileges Required: none
User Interaction: none
Scope: unchanged
Confidentiality: none
Integrity: low
Availability: none

Description

AI Translation Available

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.

290

Authentication Bypass by Spoofing

Incomplete
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Access Control
Potential Impacts:
Bypass Protection Mechanism Gain Privileges Or Assume Identity
Applicable Platforms
All platforms may be affected
View CWE Details
Application

Unbound by Nlnetlabs

Product Information
Vendor Nlnetlabs
Product Unbound
Version Range Affected
From 1.18.0 (inclusive)
To 1.25.2 (exclusive)
cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*
Common Platform Enumeration - Standardized vulnerability identification
https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-54478.t…
https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-54478.txt