CVE-2026-53921

{"id": "CVE-2026-53921", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-53921", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-10-29T13:27:12.914498Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 3.9}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "openwrt", "product": "odhcpd", "versions": [{"status": "affected", "version": "< 25.12"}]}]}], "published": "2026-10-23T14:17:53.710", "references": [{"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", "source": "security-advisories@github.com"}, {"url": "https://github.com/openwrt/odhcpd/security/advisories/GHSA-7fwx-hhrg-3496", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-121"}]}], "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."}], "lastModified": "2026-10-29T14:17:56.280", "sourceIdentifier": "security-advisories@github.com"}