Description
Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. In versions 0.9rc2 and below, avahi-daemon can be crashed via a segmentation fault by sending an unsolicited mDNS response containing a recursive CNAME record, where the alias and canonical name point to the same domain (e.g., "h.local" as a CNAME for "h.local"). This causes unbounded recursion in the lookup_handle_cname function, leading to stack exhaustion. The vulnerability affects record browsers where AVAHI_LOOKUP_USE_MULTICAST is set explicitly, which includes record browsers created by resolvers used by nss-mdns. This issue is patched in commit 78eab31128479f06e30beb8c1cbf99dd921e2524, which is part of version 0.9-rc3.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| avahi | avahi | < 0.9-rc3 | — |
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 | 0.8-18 | — |
| Debian 13 | avahi | No fix yet | — |
| Debian 12 | avahi | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 25.10 | avahi | 0.8-16ubuntu3.2 | — |
| Ubuntu 24.04 LTS | avahi | 0.8-13ubuntu6.2 | — |
| Ubuntu 22.04 LTS | avahi | 0.8-5ubuntu5.5 | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | avahi | 0.7-4ubuntu7.3+esm2 | — |
| Ubuntu Pro 18.04 LTS | avahi | 0.7-3.1ubuntu1.3+esm4 | — |
| Ubuntu Pro 16.04 LTS | avahi | 0.6.32~rc+dfsg-1ubuntu2.3+esm5 | — |
| Ubuntu Pro 14.04 LTS | avahi | 0.6.31-4ubuntu1.3+esm5 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | avahi +26 | 0.9~rc4-0.1.hum1 | RHSA-2026:11316 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | avahi +1 | 0.8-150600.15.15.1 | SUSE-SU-2026:1441-1 |
| SLES 12 SP5 | avahi | 0.6.32-32.39.1 | SUSE-SU-2026:1442-1 |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | avahi +1 | 0.8-160000.5.1 | SUSE-SU-2026:22338-1 |
| SLES 16.0 | avahi +1 | 0.8-160000.5.1 | SUSE-SU-2026:22338-1 |
| SLE Micro 6.2 | avahi | 0.8-160000.5.1 | SUSE-SU-2026:22258-1 |
| SLE Micro 6.1 | avahi | 0.8-slfo.1.1_5.1 | SUSE-SU-2026:21117-1 |
| SLE Micro 6.0 | avahi | 0.8-8.1 | SUSE-SU-2026:21127-1 |
| SLE Micro 5.5 | avahi | 0.8-150400.7.31.2 | SUSE-SU-2026:2311-1 |
| SLE Micro 5.4 | avahi | 0.8-150400.7.31.2 | SUSE-SU-2026:2311-1 |
| SLE Micro 5.3 | avahi | 0.8-150400.7.31.2 | SUSE-SU-2026:2311-1 |
| SLE Micro 5.2 | avahi | 0.7-150100.3.49.1 | SUSE-SU-2026:1191-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | avahi | 0.8-44.1 | openSUSE-SU-2026:10701-1 |
| openSUSE Leap 16.0 | avahi +2 | 0.8-160000.5.1 | openSUSE-SU-2026:21014-1 |
| openSUSE Leap 15.6 | avahi +2 | 0.8-150600.15.15.1 | SUSE-SU-2026:1441-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | avahi | 0.8-r25 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | avahi | 0.8-7 | — |
| Azure Linux 2 (CBL-Mariner) | avahi | 0.8-5 | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | avahi | 0.9_rc3-r0 | — |
Advisories 12
- RHSA-2026:11316 Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update Red Hat Security Advisories (RHSA) · Oct 6, 2026
- SUSE-SU-2026:22338-1 Security update for avahi SUSE / openSUSE Security Updates · Jul 2, 2026
- WID-SEC-2026-0211 avahi-daemon: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Jul 1, 2026
- openSUSE-SU-2026:21014-1 Security update for avahi SUSE / openSUSE Security Updates · Jun 30, 2026
- SUSE-SU-2026:22258-1 Security update for avahi SUSE / openSUSE Security Updates · Jun 30, 2026
- SUSE-SU-2026:2311-1 Security update for avahi SUSE / openSUSE Security Updates · Jun 10, 2026
- openSUSE-SU-2026:10701-1 avahi-0.8-44.1 on GA media SUSE / openSUSE Security Updates · May 7, 2026
- SUSE-SU-2026:21117-1 Security update for avahi SUSE / openSUSE Security Updates · Apr 18, 2026
- SUSE-SU-2026:21127-1 Security update for avahi SUSE / openSUSE Security Updates · Apr 18, 2026
- SUSE-SU-2026:1442-1 Security update for avahi SUSE / openSUSE Security Updates · Apr 18, 2026
- SUSE-SU-2026:1441-1 Security update for avahi SUSE / openSUSE Security Updates · Apr 18, 2026
- SUSE-SU-2026:1191-1 Security update for avahi SUSE / openSUSE Security Updates · Apr 8, 2026