Daemon crash via recursive CNAME lookup
Published Jan 24, 2026 · Updated Jan 24, 2026
Uncontrolled recursion in Avahi 0.9-rc2 and earlier allows remote attackers to crash avahi-daemon with a recursive mDNS CNAME response. lookup_handle_cname follows a self-referential alias without detecting that the CNAME target is already in its lookup path, exhausting the stack. The daemon is exposed only while a multicast-enabled record browser is active, including a resolver browser created by nss-mdns, and a crafted unsolicited LAN response terminates the process.
Summary
What happened
Uncontrolled recursion in Avahi 0.9-rc2 and earlier allows remote attackers to crash avahi-daemon with a recursive mDNS CNAME response. lookup_handle_cname follows a self-referential alias without detecting that the CNAME target is already in its lookup path, exhausting the stack. The daemon is exposed only while a multicast-enabled record browser is active, including a resolver browser created by nss-mdns, and a crafted unsolicited LAN response terminates the process.
The record
- CVE
- CVE-2026-24401
- Published
- Jan 24, 2026
- Updated
- Jan 24, 2026
- Vendor
- Avahi
- Product
- Avahi
- Classifications
- CWE-674, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 24, 2026CVE publishedPublication date reported by the CVE source.
- Jan 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=< 78eab31128479f06e30beb8c1cbf99dd921e2524
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Self-referential CNAME Scapy packetfunctional · demonstrated
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Technologies
Your stack
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Your stack
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