avahi — security advisory

{
  "id": "2f7a52526a3cdaaa2e3941987d9bda4270bde501d27057f8bc72fa18a87a6c7a",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2025-59529",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2025-59529",
    "summary": "Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. In versions up to and including 0.9-rc5, the simple protocol server ignores the documented client limit and accepts unlimited connections, allowing for easy local DoS. Although `CLIENTS_MAX` is defined, `server_work()` unconditionally `accept()`s and `client_new()` always appends the new client and increments `n_clients`. There is no check against the limit. When client cannot be accepted as a result of maximal socket number of avahi-daemon, it logs unconditionally error per each connection. Unprivileged local users can exhaust daemon memory and file descriptors, causing a denial of service system-wide for mDNS/DNS-SD. Exhausting local file descriptors causes increased system load caused by logging errors of each of request. Overloading prevents glibc calls using nss-mdns plugins to resolve `*.local.` names and link-local addresses. As of time of publication, no known patched versions are available, but a candidate fix is available in pull request 808, and some workarounds are available. Simple clients are offered for nss-mdns package functionality. It is not possible to disable the unix socket `/run/avahi-daemon/socket`, but resolution requests received via DBus are not affected directly. Tools avahi-resolve, avahi-resolve-address and avahi-resolve-host-name are not affected, they use DBus interface. It is possible to change permissions of unix socket after avahi-daem",
    "evidence": "osv:DEBIAN-CVE-2025-59529",
    "products": [
      {
        "name": {
          "value": "avahi",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "0.8-10",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.8-10+deb12u1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.8-11",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.8-12",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.8-13",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.8-14",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.8-15",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.8-16",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.8-17",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.8-18",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "avahi",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "0.8-16",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "0.8-17",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "0.8-18",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "avahi",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "0.8-16",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "0.8-17",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "0.8-18",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2025-59529",
      "aliases": [
        "DEBIAN-CVE-2025-59529"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "avahi",
            "purl": "pkg:deb/debian/avahi?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "0.8-10",
            "0.8-10+deb12u1",
            "0.8-11",
            "0.8-12",
            "0.8-13",
            "0.8-14",
            "0.8-15",
            "0.8-16",
            "0.8-17",
            "0.8-18"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-59529.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "avahi",
            "purl": "pkg:deb/debian/avahi?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "0.8-16",
            "0.8-17",
            "0.8-18"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-59529.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "avahi",
            "purl": "pkg:deb/debian/avahi?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "0.8-16",
            "0.8-17",
            "0.8-18"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-59529.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-24T09:47:23.938513887Z",
      "provider": "osv",
      "upstream": [
        "CVE-2025-59529"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2025-59529"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2025-59529",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 428937,
  "published_at": "2025-12-18T21:15:53.637+00:00"
}