Vulnerability in Avahi
CVE-2026-24401
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.003 (20.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000
Affected products
- Avahi — versions 0.9, < 78eab31128479f06e30beb8c1cbf99dd921e2524
Weakness classification (CWE)
References
- github.com/avahi/avahi/security/advisories/GHSA-h4vp-5m8j-f6w3 (Vendor Advisory)
- github.com/avahi/avahi/issues/501 (Patch, Issue Tracking)
- github.com/avahi/avahi/commit/78eab31128479f06e30beb8c1cbf99dd921e2524 (Patch)
Frequently asked questions
- What is CVE-2026-24401?
- CVE-2026-24401 is a medium-severity vulnerability in Avahi, classified under Uncontrolled Recursion. CVSS score: 6.5/10. Published 2026-01-24.
- How severe is CVE-2026-24401?
- Medium severity. CVSS v3 base score is 6.5 out of 10.