{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-53921", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-06-11T15:46:12.316Z", "datePublished": "2026-10-23T13:20:30.249Z", "dateUpdated": "2026-10-23T13:20:30.249Z"}, "containers": {"cna": {"title": "odhcpd: Stack buffer overflow in DHCPv6 IA reply serialization (2 independent sites)", "problemTypes": [{"descriptions": [{"cweId": "CWE-121", "lang": "en", "description": "CWE-121: Stack-based Buffer Overflow", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}}], "references": [{"name": "https://github.com/openwrt/odhcpd/security/advisories/GHSA-7fwx-hhrg-3496", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/openwrt/odhcpd/security/advisories/GHSA-7fwx-hhrg-3496"}, {"name": "https://github.com/openwrt/odhcpd/commit/0320032ae313452f3c8cb8725c621dd06c36dc03", "tags": ["x_refsource_MISC"], "url": "https://github.com/openwrt/odhcpd/commit/0320032ae313452f3c8cb8725c621dd06c36dc03"}, {"name": "https://github.com/openwrt/odhcpd/commit/03dacc23356b5789842b9d1bba0200fd005e35f3", "tags": ["x_refsource_MISC"], "url": "https://github.com/openwrt/odhcpd/commit/03dacc23356b5789842b9d1bba0200fd005e35f3"}, {"name": "https://github.com/openwrt/odhcpd/commit/2a42d34c3615e2449ca273f673eee7c429d819a9", "tags": ["x_refsource_MISC"], "url": "https://github.com/openwrt/odhcpd/commit/2a42d34c3615e2449ca273f673eee7c429d819a9"}, {"name": "https://github.com/openwrt/odhcpd/commit/6634b7a3c79c41a27687925c98c35c8aea2f2b5a", "tags": ["x_refsource_MISC"], "url": "https://github.com/openwrt/odhcpd/commit/6634b7a3c79c41a27687925c98c35c8aea2f2b5a"}, {"name": "https://github.com/openwrt/odhcpd/commit/d168c27fb6a55a07ac4c888e09ff2f41e263d7b7", "tags": ["x_refsource_MISC"], "url": "https://github.com/openwrt/odhcpd/commit/d168c27fb6a55a07ac4c888e09ff2f41e263d7b7"}, {"name": "https://github.com/openwrt/odhcpd/commit/d329a15413387027453644cd363dca06ade28328", "tags": ["x_refsource_MISC"], "url": "https://github.com/openwrt/odhcpd/commit/d329a15413387027453644cd363dca06ade28328"}], "affected": [{"vendor": "openwrt", "product": "odhcpd", "versions": [{"version": "< 25.12", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-10-23T13:20:30.249Z"}, "descriptions": [{"lang": "en", "value": "odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. Prior to version 25.12, odhcpd's DHCPv6 IA response handler writes past the end of a fixed 512-byte stack buffer (pdbuf) when a single DHCPv6 REQUEST carries enough IA options to nearly exhaust the reply space. Two independent overflow sites exist in the same call chain, both reachable from the network via a single unauthenticated UDP packet. odhcpd runs as root on OpenWrt; embedded targets often lack stack canaries and ASLR, making code execution realistic. This issue has been patched in version 25.12."}], "source": {"advisory": "GHSA-7fwx-hhrg-3496", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "odhcpd", "vendor": "openwrt", "versions": [{"status": "affected", "version": "< 25.12"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. Prior to version 25.12, odhcpd's DHCPv6 IA response handler writes past the end of a fixed 512-byte stack buffer (pdbuf) when a single DHCPv6 REQUEST carries enough IA options to nearly exhaust the reply space. Two independent overflow sites exist in the same call chain, both reachable from the network via a single unauthenticated UDP packet. odhcpd runs as root on OpenWrt; embedded targets often lack stack canaries and ASLR, making code execution realistic. This issue has been patched in version 25.12."}], "id": "CVE-2026-53921", "lastModified": "2026-10-23T19:37:11.060", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-10-23T14:17:53.710", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/openwrt/odhcpd/commit/0320032ae313452f3c8cb8725c621dd06c36dc03"}, {"source": "security-advisories@github.com", "url": "https://github.com/openwrt/odhcpd/commit/03dacc23356b5789842b9d1bba0200fd005e35f3"}, {"source": "security-advisories@github.com", "url": "https://github.com/openwrt/odhcpd/commit/2a42d34c3615e2449ca273f673eee7c429d819a9"}, {"source": "security-advisories@github.com", "url": "https://github.com/openwrt/odhcpd/commit/6634b7a3c79c41a27687925c98c35c8aea2f2b5a"}, {"source": "security-advisories@github.com", "url": "https://github.com/openwrt/odhcpd/commit/d168c27fb6a55a07ac4c888e09ff2f41e263d7b7"}, {"source": "security-advisories@github.com", "url": "https://github.com/openwrt/odhcpd/commit/d329a15413387027453644cd363dca06ade28328"}, {"source": "security-advisories@github.com", "url": "https://github.com/openwrt/odhcpd/security/advisories/GHSA-7fwx-hhrg-3496"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-121"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}