{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-24401", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-01-22T18:19:49.172Z", "datePublished": "2026-01-24T01:25:02.294Z", "dateUpdated": "2026-01-26T16:17:24.487Z"}, "containers": {"cna": {"title": "Avahi has Uncontrolled Recursion in lookup_handle_cname function", "problemTypes": [{"descriptions": [{"cweId": "CWE-674", "lang": "en", "description": "CWE-674: Uncontrolled Recursion", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "version": "3.1"}}], "references": [{"name": "https://github.com/avahi/avahi/security/advisories/GHSA-h4vp-5m8j-f6w3", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/avahi/avahi/security/advisories/GHSA-h4vp-5m8j-f6w3"}, {"name": "https://github.com/avahi/avahi/issues/501", "tags": ["x_refsource_MISC"], "url": "https://github.com/avahi/avahi/issues/501"}, {"name": "https://github.com/avahi/avahi/commit/78eab31128479f06e30beb8c1cbf99dd921e2524", "tags": ["x_refsource_MISC"], "url": "https://github.com/avahi/avahi/commit/78eab31128479f06e30beb8c1cbf99dd921e2524"}], "affected": [{"vendor": "avahi", "product": "avahi", "versions": [{"version": "< 78eab31128479f06e30beb8c1cbf99dd921e2524", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-01-24T01:25:02.294Z"}, "descriptions": [{"lang": "en", "value": "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."}], "source": {"advisory": "GHSA-h4vp-5m8j-f6w3", "discovery": "UNKNOWN"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-01-26T16:14:24.982686Z", "id": "CVE-2026-24401", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-01-26T16:17:24.487Z"}}]}}

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{"cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-24401", "lastModified": "2026-01-26T15:03:33.357", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-01-24T02:15:48.760", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/avahi/avahi/commit/78eab31128479f06e30beb8c1cbf99dd921e2524"}, {"source": "security-advisories@github.com", "url": "https://github.com/avahi/avahi/issues/501"}, {"source": "security-advisories@github.com", "url": "https://github.com/avahi/avahi/security/advisories/GHSA-h4vp-5m8j-f6w3"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-674"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{"bugzilla": {"description": "avahi: Avahi: Denial of Service via recursive CNAME record in mDNS response", "id": "2432534", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2432534"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-674", "details": ["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.", "A flaw was found in Avahi, a system that enables devices to discover services on a local network. A remote attacker can exploit this vulnerability by sending a specially crafted mDNS (multicast Domain Name System) response containing a recursive CNAME (Canonical Name) record. This triggers an uncontrolled recursion within the avahi-daemon process, leading to stack exhaustion and causing the service to crash. This results in a denial of service (DoS) for affected systems."], "mitigation": {"lang": "en:us", "value": "To mitigate this issue, disable the avahi-daemon service if mDNS/DNS-SD functionality is not required on the system.\n```bash\nsudo systemctl disable --now avahi-daemon.service\nsudo systemctl mask avahi-daemon.service\n```\nDisabling this service may impact applications relying on mDNS for local network service discovery. A system reboot or service reload may be required for the changes to take full effect."}, "name": "CVE-2026-24401", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "avahi", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Fix deferred", "package_name": "avahi", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "avahi", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "avahi", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "avahi", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-01-24T01:25:02Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-24401\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-24401\nhttps://github.com/avahi/avahi/commit/78eab31128479f06e30beb8c1cbf99dd921e2524\nhttps://github.com/avahi/avahi/issues/501\nhttps://github.com/avahi/avahi/security/advisories/GHSA-h4vp-5m8j-f6w3"], "statement": "This MODERATE impact flaw in Avahi's `avahi-daemon` can lead to a denial of service. An attacker on the local network could send a specially crafted, unsolicited mDNS response containing a recursive CNAME record, causing unbounded recursion and a crash. This affects systems where Avahi's record browsers explicitly use multicast, such as those utilizing `nss-mdns`.", "threat_severity": "Moderate"}