ubuntu-cve-2026-56113
Vulnerability from osv_ubuntu
Published
2026-06-23 17:17
Modified
2026-06-29 11:36
Summary
Details

dhcpcd through 10.3.2, fixed in commit 5733d3c, contains a heap use-after-free vulnerability that allows unauthenticated same-link attackers to crash the daemon by sending a crafted DHCPv6 RENEW reply with RFC6603 OPTION_PD_EXCLUDE and both preferred and valid lifetimes set to zero. Attackers acting as or impersonating a DHCPv6 server can trigger dhcp6_deprecatedele() to free a delegated child address while an outer TAILQ_FOREACH_SAFE iterator in dhcp6_deprecateaddrs() still holds the freed pointer, causing a use-after-free when TAILQ_REMOVE is reached.

Severity
5.3 (Medium)
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
6.5 (Medium)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.0 (Medium)
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "dhcpcd",
            "binary_version": "1:10.0.6-1ubuntu3.2"
          },
          {
            "binary_name": "dhcpcd-base",
            "binary_version": "1:10.0.6-1ubuntu3.2"
          },
          {
            "binary_name": "dhcpcd5",
            "binary_version": "1:10.0.6-1ubuntu3.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "dhcpcd",
        "purl": "pkg:deb/ubuntu/dhcpcd@1:10.0.6-1ubuntu3.2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:10.0.2-3ubuntu3",
        "1:10.0.5-1",
        "1:10.0.5-2",
        "1:10.0.5-3",
        "1:10.0.5-4",
        "1:10.0.5-5",
        "1:10.0.6-1",
        "1:10.0.6-1ubuntu1",
        "1:10.0.6-1ubuntu2",
        "1:10.0.6-1ubuntu3",
        "1:10.0.6-1ubuntu3.1",
        "1:10.0.6-1ubuntu3.2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "dhcpcd",
            "binary_version": "1:10.2.4-4"
          },
          {
            "binary_name": "dhcpcd-base",
            "binary_version": "1:10.2.4-4"
          },
          {
            "binary_name": "dhcpcd5",
            "binary_version": "1:10.2.4-4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "dhcpcd",
        "purl": "pkg:deb/ubuntu/dhcpcd@1:10.2.4-4?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:10.1.0-8",
        "1:10.1.0-10",
        "1:10.1.0-11",
        "1:10.1.0-12",
        "1:10.2.4-3",
        "1:10.2.4-4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "dhcpcd",
            "binary_version": "1:10.3.0-7"
          },
          {
            "binary_name": "dhcpcd-base",
            "binary_version": "1:10.3.0-7"
          },
          {
            "binary_name": "dhcpcd5",
            "binary_version": "1:10.3.0-7"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "dhcpcd",
        "purl": "pkg:deb/ubuntu/dhcpcd@1:10.3.0-7?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:10.2.4-4",
        "1:10.3.0-2",
        "1:10.3.0-3",
        "1:10.3.0-7"
      ]
    }
  ],
  "aliases": [],
  "details": "dhcpcd through 10.3.2, fixed in commit 5733d3c, contains a heap use-after-free vulnerability that allows unauthenticated same-link attackers to crash the daemon by sending a crafted DHCPv6 RENEW reply with RFC6603 OPTION_PD_EXCLUDE and both preferred and valid lifetimes set to zero. Attackers acting as or impersonating a DHCPv6 server can trigger dhcp6_deprecatedele() to free a delegated child address while an outer TAILQ_FOREACH_SAFE iterator in dhcp6_deprecateaddrs() still holds the freed pointer, causing a use-after-free when TAILQ_REMOVE is reached.",
  "id": "UBUNTU-CVE-2026-56113",
  "modified": "2026-06-29T11:36:36Z",
  "published": "2026-06-23T17:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-56113"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-56113"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-56113"
  ]
}



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