CVE-2026-24401
Publication date 24 January 2026
Last updated 14 May 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| avahi | 26.04 LTS resolute |
Fixed 0.8-18ubuntu1.1
|
| 25.10 questing |
Fixed 0.8-16ubuntu3.2
|
|
| 24.04 LTS noble |
Fixed 0.8-13ubuntu6.2
|
|
| 22.04 LTS jammy |
Fixed 0.8-5ubuntu5.5
|
|
| 20.04 LTS focal |
Fixed 0.7-4ubuntu7.3+esm2
|
|
| 18.04 LTS bionic |
Fixed 0.7-3.1ubuntu1.3+esm4
|
|
| 16.04 LTS xenial |
Fixed 0.6.32~rc+dfsg-1ubuntu2.3+esm5
|
|
| 14.04 LTS trusty |
Fixed 0.6.31-4ubuntu1.3+esm5
|
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| Parameter | Value |
|---|---|
| Base score |
6.5 · Medium
|
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | Required |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | None |
| Availability impact | High |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |
References
Related Ubuntu Security Notices (USN)
- USN-8269-1
- Avahi vulnerabilities
- 12 May 2026