Description
The originates_from_local_legacy_unicast_socket function in avahi-core/server.c in avahi-daemon 0.6.23 does not account for the network byte order of a port number when processing incoming multicast packets, which allows remote attackers to cause a denial of service (network bandwidth and CPU consumption) via a crafted legacy unicast mDNS query packet that triggers a multicast packet storm.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | avahi | 0.6.24-3 | — |
| Debian 13 | avahi | 0.6.24-3 | — |
| Debian 12 | avahi | 0.6.24-3 | — |
| Debian 5.0 | avahi | 0.6.23-3lenny2 | DSA-2086-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | avahi +10 | 0.6.16-9.el5_5 | RHSA-2010:0528 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | avahi | 0.6.32-2.3 | openSUSE-SU-2024:10363-1 |
Advisories 3
- RHSA-2010:0528 Red Hat Security Advisory: avahi security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-2086-1 avahi - denial of service Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10363-1 avahi-0.6.32-2.3 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- [oss-security] 20090302 CVE id request: avahi mailing-list
- MDVSA-2009:076 vendor-advisory
- DSA-2086 vendor-advisory
- SUSE-SR:2010:002 vendor-advisory
- http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=517683
- 33946 vdb-entry
- 38420 third-party-advisory