PT-2025-47321 · Avahi+2 · Avahi+2

Pemensik · Published 2025-11-18 · Updated 2026-02-16 · CVE-2025-59529

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Avahi versions up to and including 0.9-rc2

Description Avahi is a system that enables service discovery on a local network using the mDNS/DNS-SD protocol suite. The simple protocol server does not enforce the documented client limit, accepting an unlimited number of connections. This allows unprivileged local users to exhaust the daemon's memory and file descriptors, leading to a denial of service system-wide for mDNS/DNS-SD. The issue stems from the server work() function unconditionally accepting connections and the client new() function always appending new clients without checking against the CLIENTS MAX limit. Exhausting local file descriptors results in increased system load due to error logging for each connection attempt. Overloading the system prevents glibc calls using nss-mdns plugins from resolving *.local. names and link-local addresses. Tools like avahi-resolve, avahi-resolve-address, and avahi-resolve-host-name, which use the DBus interface, are not directly affected.

Recommendations Versions prior to 0.9-rc2 are affected. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

DoS

Resource Exhaustion

Weakness Enumeration

CWE-400

Related Identifiers

AZL-72851

AZL-72853

BDU:2026-03596

CVE-2025-59529

ECHO-7E9E-9AC7-D59B

GHSA-73WF-3XMJ-X82Q

Affected Products

Avahi

Debian

Red Os

References · 27

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/59xxx/CVE-2025-59529.json · Exploit
• 🔥 https://zeropath.com/blog/avahi-simple-protocol-server-dos-cve-2025-59529 · Exploit
• 🔥 http://openwall.com/lists/oss-security/2025/12/19/1 · Exploit
• https://github.com/avahi/avahi/pull/808 · Patch
• https://github.com/avahi/avahi/security/advisories/GHSA-73wf-3xmj-x82q · Vendor Advisory
• https://osv.dev/vulnerability/AZL-72851 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2025-59529 · Vendor Advisory
• https://osv.dev/vulnerability/AZL-72853 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-59529 · Security Note
• https://bdu.fstec.ru/vul/2026-03596 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2025-59529 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2025-59529 · Security Note
• https://ubuntu.com/security/CVE-2025-59529 · Vendor Advisory
• https://osv.dev/vulnerability/ROOT-OS-DEBIAN-13-CVE-2025-59529 · Vendor Advisory
• https://osv.dev/vulnerability/BELL-CVE-2025-59529 · Vendor Advisory