SB2025072110 - Fedora 42 update for unbound



SB2025072110 - Fedora 42 update for unbound

Published: July 21, 2025

Security Bulletin ID SB2025072110
Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 security vulnerability.


1) Acceptance of Extraneous Untrusted Data With Trusted Data (CVE-ID: CVE-2025-5994)

The vulnerability allows a remote attacker to perform cache poisoning attacks.

The vulnerability exists due to a logic error in the EDNS Client Subnet (ECS) implementation. A remote attacker can perform cache poisoning attacks against Unbound servers with ECS support, a.k.a. Rebirthday Attack.

Successful exploitation of the vulnerability requires that the server is compiled with '--enable-subnet' and configured to send ECS information to upstream name servers with at least one of the 'send-client-subnet', 'client-subnet-zone' or 'client-subnet-always-forward' options.


Remediation

Install update from vendor's website.