Incorrect Implementation of Authentication Algorithm Affecting unbound package, versions [1.18.0,1.25.2)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published2 Aug 2026
- disclosed22 Jul 2026
- creditUnknown
Introduced: 22 Jul 2026
NewCVE-2026-54478 (opens in a new tab)How to fix?
Upgrade unbound to version 1.25.2 or higher.
Overview
Affected versions of this package are vulnerable to Incorrect Implementation of Authentication Algorithm via the incorrect calculation of the server cookie in the process. An attacker can bypass intended security restrictions by replaying a harvested cookie from a spoofed source. This is only exploitable if both proxy-protocol-port and answer-cookie: yes are enabled in the configuration.
Workaround
This vulnerability can be mitigated by avoiding the simultaneous use of answer-cookie: yes and proxy-protocol-port, disabling DNS cookies if the proxy protocol is required, or ensuring the proxy infrastructure is secured and trusted.