CVE-2026-53922 (GCVE-0-2026-53922)

Vulnerability from cvelistv5 – Published: 2026-10-12 21:31 – Updated: 2026-10-12 21:31
VLAI
Title
odhcpd: pre-auth remote DoS via size_t underflow in dhcpv6_ia_handle_IAs (stack BOF, canary-terminated)
Summary
odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In commit cfddd56 and earlier, an unauthenticated host on the same link can first obtain two bindings through normal DHCPv6 SOLICIT and REQUEST exchanges and then send a crafted RENEW containing multiple IA_NA options. An earlier matched IA consumes most of the response buffer, an unmatched IA causes the build_ia() status branch to write and return a NOBINDING response larger than the remaining space, and a subsequent matched IA is processed after dhcpv6_ia_handle_IAs() subtracts that over-return from an unsigned size_t. The resulting underflow disables subsequent length checks and permits attacker-controlled IA_ADDR serialization beyond the 512-byte stack buffer pdbuf in handle_client_request(). The stack canary terminates odhcpd, and sustained packets can repeatedly disrupt DHCPv6 service while procd respawns the process. The observed configuration does not establish code execution.
Severity
6.5 (Medium)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
  • CWE-121 - Stack-based Buffer Overflow
  • CWE-191 - Integer Underflow (Wrap or Wraparound)
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7566 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
openwrt odhcpd Affected: < c6792bac3905d4bf726d914e9994f6d4b98c5b57
guessed Create a notification for this product.
openwrt openwrt Affected: < 25.12.5
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "odhcpd",
          "vendor": "openwrt",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c c6792bac3905d4bf726d914e9994f6d4b98c5b57"
            }
          ]
        },
        {
          "product": "openwrt",
          "vendor": "openwrt",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 25.12.5"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In commit cfddd56 and earlier, an unauthenticated host on the same link can first obtain two bindings through normal DHCPv6 SOLICIT and REQUEST exchanges and then send a crafted RENEW containing multiple IA_NA options. An earlier matched IA consumes most of the response buffer, an unmatched IA causes the build_ia() status branch to write and return a NOBINDING response larger than the remaining space, and a subsequent matched IA is processed after dhcpv6_ia_handle_IAs() subtracts that over-return from an unsigned size_t. The resulting underflow disables subsequent length checks and permits attacker-controlled IA_ADDR serialization beyond the 512-byte stack buffer pdbuf in handle_client_request(). The stack canary terminates odhcpd, and sustained packets can repeatedly disrupt DHCPv6 service while procd respawns the process. The observed configuration does not establish code execution."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "ADJACENT_NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
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              "type": "CWE"
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        {
          "descriptions": [
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            }
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-12T21:31:24.809Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
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          "name": "https://github.com/openwrt/odhcpd/security/advisories/GHSA-7hcw-g2jh-pqv5",
          "tags": [
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          "url": "https://github.com/openwrt/odhcpd/security/advisories/GHSA-7hcw-g2jh-pqv5"
        },
        {
          "name": "https://github.com/openwrt/odhcpd/commit/c6792bac3905d4bf726d914e9994f6d4b98c5b57",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/openwrt/odhcpd/commit/c6792bac3905d4bf726d914e9994f6d4b98c5b57"
        },
        {
          "name": "https://github.com/openwrt/odhcpd/commit/d08dbcc527cb8f296cd132c1e5bca696e77095b8",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/openwrt/odhcpd/commit/d08dbcc527cb8f296cd132c1e5bca696e77095b8"
        },
        {
          "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"
        },
        {
          "name": "https://github.com/openwrt/openwrt/releases/tag/v25.12.5",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/openwrt/openwrt/releases/tag/v25.12.5"
        }
      ],
      "source": {
        "advisory": "GHSA-7hcw-g2jh-pqv5",
        "discovery": "UNKNOWN"
      },
      "title": "odhcpd: pre-auth remote DoS via size_t underflow in dhcpv6_ia_handle_IAs (stack BOF, canary-terminated)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-53922",
    "datePublished": "2026-10-12T21:31:24.809Z",
    "dateReserved": "2026-06-11T15:46:12.316Z",
    "dateUpdated": "2026-10-12T21:31:24.809Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": {
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                "product": "odhcpd",
                "vendor": "openwrt",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c c6792bac3905d4bf726d914e9994f6d4b98c5b57"
                  }
                ]
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              {
                "product": "openwrt",
                "vendor": "openwrt",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 25.12.5"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. In commit cfddd56 and earlier, an unauthenticated host on the same link can first obtain two bindings through normal DHCPv6 SOLICIT and REQUEST exchanges and then send a crafted RENEW containing multiple IA_NA options. An earlier matched IA consumes most of the response buffer, an unmatched IA causes the build_ia() status branch to write and return a NOBINDING response larger than the remaining space, and a subsequent matched IA is processed after dhcpv6_ia_handle_IAs() subtracts that over-return from an unsigned size_t. The resulting underflow disables subsequent length checks and permits attacker-controlled IA_ADDR serialization beyond the 512-byte stack buffer pdbuf in handle_client_request(). The stack canary terminates odhcpd, and sustained packets can repeatedly disrupt DHCPv6 service while procd respawns the process. The observed configuration does not establish code execution."
          }
        ],
        "id": "CVE-2026-53922",
        "lastModified": "2026-10-12T22:17:04.623",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "ADJACENT_NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 6.5,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
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              "impactScore": 3.6,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-10-12T22:17:04.623",
        "references": [
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            "source": "security-advisories@github.com",
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          },
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            "source": "security-advisories@github.com",
            "url": "https://github.com/openwrt/odhcpd/commit/d168c27fb6a55a07ac4c888e09ff2f41e263d7b7"
          },
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            "url": "https://github.com/openwrt/odhcpd/commit/d329a15413387027453644cd363dca06ade28328"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/openwrt/odhcpd/security/advisories/GHSA-7hcw-g2jh-pqv5"
          },
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            "source": "security-advisories@github.com",
            "url": "https://github.com/openwrt/openwrt/releases/tag/v25.12.5"
          }
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        "vulnStatus": "Received",
        "weaknesses": [
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                "value": "CWE-121"
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              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}



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