{"id":"CVE-2026-53920","state":"PUBLISHED","title":"odhcpd DHCPv6 Short IA_NA/IA_PD Body Stack Disclosure","description":"odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. From version 17.01.0 to before version 25.12.3, odhcpd's DHCPv6 IA parser accepts an IA_NA or IA_PD option whose body is shorter than struct dhcpv6_ia_hdr, casts the option header to that full structure, and reads ia->iaid before proving that the IA body contains the IAID field. If an unauthenticated network-adjacent client places a zero-length or otherwise short IA option at the end of odhcpd's 8192-byte receive stack buffer, the IAID read crosses from data_buf into adjacent stack memory. The disclosed bytes are then reflected in the DHCPv6 reply IAID; prior ARM validation showed data_buf[8192:8196] disclosing the saved stack canary, and wider stack scans can leak ASLR-useful stack/process contents. This issue has been patched in version 25.12.3.","publishedAt":"2026-10-23T13:20:48.045Z","updatedAt":"2026-10-23T20:58:10.536Z","severity":{"score":8.7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["openwrt odhcpd"],"affected":[{"vendor":"openwrt","product":"odhcpd","versions":[{"version":">= 17.01.0, < 25.12.3","status":"affected"}]}],"references":["https://github.com/openwrt/odhcpd/security/advisories/GHSA-p769-5v73-pc4f","https://github.com/openwrt/odhcpd/commit/719fc3abc0d7e7059871f9f572fb05ada86b8ff2","https://github.com/openwrt/odhcpd/commit/f2275efc72a87a95f971f159babcbadc5d241d42"],"weaknesses":["CWE-125","CWE-126","CWE-200","CWE-201"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53920.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53920","state":"PUBLISHED","datePublished":"2026-10-23T13:20:48.045Z","dateUpdated":"2026-10-23T20:58:10.536Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-11T15:46:12.316Z"},"containers":{"cna":{"title":"odhcpd DHCPv6 Short IA_NA/IA_PD Body Stack Disclosure","descriptions":[{"lang":"en","value":"odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. From version 17.01.0 to before version 25.12.3, odhcpd's DHCPv6 IA parser accepts an IA_NA or IA_PD option whose body is shorter than struct dhcpv6_ia_hdr, casts the option header to that full structure, and reads ia->iaid before proving that the IA body contains the IAID field. If an unauthenticated network-adjacent client places a zero-length or otherwise short IA option at the end of odhcpd's 8192-byte receive stack buffer, the IAID read crosses from data_buf into adjacent stack memory. The disclosed bytes are then reflected in the DHCPv6 reply IAID; prior ARM validation showed data_buf[8192:8196] disclosing the saved stack canary, and wider stack scans can leak ASLR-useful stack/process contents. This issue has been patched in version 25.12.3."}],"affected":[{"vendor":"openwrt","product":"odhcpd","versions":[{"version":">= 17.01.0, < 25.12.3","status":"affected"}]}],"references":[{"url":"https://github.com/openwrt/odhcpd/security/advisories/GHSA-p769-5v73-pc4f","name":"https://github.com/openwrt/odhcpd/security/advisories/GHSA-p769-5v73-pc4f","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/openwrt/odhcpd/commit/719fc3abc0d7e7059871f9f572fb05ada86b8ff2","name":"https://github.com/openwrt/odhcpd/commit/719fc3abc0d7e7059871f9f572fb05ada86b8ff2","tags":["x_refsource_MISC"]},{"url":"https://github.com/openwrt/odhcpd/commit/f2275efc72a87a95f971f159babcbadc5d241d42","name":"https://github.com/openwrt/odhcpd/commit/f2275efc72a87a95f971f159babcbadc5d241d42","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.7,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","description":"CWE-125: Out-of-bounds Read","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-126","lang":"en","description":"CWE-126: Buffer Over-read","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-200","lang":"en","description":"CWE-200: Exposure of Sensitive Information to an Unauthorized Actor","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-201","lang":"en","description":"CWE-201: Insertion of Sensitive Information Into Sent Data","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-23T13:20:48.045Z"},"source":{"advisory":"GHSA-p769-5v73-pc4f","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-23T17:33:12.791918Z","id":"CVE-2026-53920","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-23T20:58:10.536Z"}}]}}}