{"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":"2026-10-29T13:28:11.455Z"},"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"}},"adp":[{"references":[{"url":"https://github.com/openwrt/odhcpd/security/advisories/GHSA-7fwx-hhrg-3496","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-29T13:27:12.914498Z","id":"CVE-2026-53921","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-10-29T13:28:11.455Z"}}]}}