{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "odhcpd",
          "vendor": "openwrt",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 25.12"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. Prior to version 25.12, odhcpd\u0027s 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."
        }
      ],
      "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"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-121",
              "description": "CWE-121: Stack-based Buffer Overflow",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-23T13:20:30.249Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "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"
        }
      ],
      "source": {
        "advisory": "GHSA-7fwx-hhrg-3496",
        "discovery": "UNKNOWN"
      },
      "title": "odhcpd: Stack buffer overflow in DHCPv6 IA reply serialization (2 independent sites)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-53921",
    "datePublished": "2026-10-23T13:20:30.249Z",
    "dateReserved": "2026-06-11T15:46:12.316Z",
    "dateUpdated": "2026-10-23T13:20:30.249Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}