Input validation error in Avahi - CVE-2026-58406
Published: July 12, 2026
Vulnerability identifier: #VU137341
CSH Severity: Medium
CVSS v4: 7.1 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-58406
CWE-ID: CWE-20
Exploitation vector: Adjecent network
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 improper input validation in avahi_domain_hash when processing mDNS resource records with names containing bytes greater than or equal to 128. A remote attacker can send a specially crafted multicast DNS response packet to cause a denial of service.
The issue affects NetBSD systems on architectures where char is signed and invalid ctype(3) inputs trigger a SIGSEGV.
Affected software
Avahi
How to mitigate CVE-2026-58406
Install security update from vendor's website.
Avahi - update to 0.9 rc5