Resource exhaustion in Unbound - CVE-2026-80225
Published: September 16, 2026 / Updated: September 19, 2026
Vulnerability identifier: #VU150191
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-80225
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in Unbound's TCP/DoT reading procedure when processing a sustained stream of distinct uncached names over a TCP/DoT connection. A remote attacker can stream distinct uncached names at a sustained rate to cause a denial of service.
Affected software
Unbound
Fedora
unbound
Fedora
unbound
How to mitigate CVE-2026-80225
Install security update from vendor's website.
Unbound - update to 1.26.1
unbound - addressed in versions 1.26.1-1.fc43, 1.26.1-1.fc44, 1.26.1-1.fc45
unbound - addressed in versions 1.26.1-1.fc43, 1.26.1-1.fc44, 1.26.1-1.fc45