In versions 0.9rc2 and below, avahi-daemon can be crashed via a segmentation fault by sending an unsolicited mDNS
Affects avahiSource GCVE Database
Not known to be exploited · CVSS 6.5 Medium · fixed in 0.6.31-4ubuntu1.3+esm5 : update avahi when convenient.
Data as of 28 Oct 2026, 22:28 UTC
- Patch
- Available – fixed in 0.6.31-4ubuntu1.3+esm5, 0.6.32~rc+dfsg-1ubuntu2.3+esm5, 0.7-3.1ubuntu1.3+esm4 +4
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10avahipkg:deb/ubuntu/avahi?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSavahipkg:deb/ubuntu/avahi?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 22.04 LTSavahipkg:deb/ubuntu/avahi?arch=source&distro=jammyOther threats | Affected
| Fixed in
|
Ubuntu Pro 20.04 LTSavahipkg:deb/ubuntu/avahi?arch=source&distro=esm-infra/focalOther threats | Affected
| Fixed in
|
Ubuntu Pro 18.04 LTSavahipkg:deb/ubuntu/avahi?arch=source&distro=esm-infra/bionicOther threats | Affected
| Fixed in
|
Ubuntu Pro 16.04 LTSavahipkg:deb/ubuntu/avahi?arch=source&distro=esm-infra/xenialOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.