{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "ec8a8f3c31ddef0a7d9626c4b8a4baa30f3b80aa"
            },
            {
              "fixed": "bcb50aa0b8f2b74a9fe5a1c7bee6f2657a288041"
            },
            {
              "fixed": "2a3aac4205e7d2f1aca2e3827de8cdd517d36c4a"
            },
            {
              "fixed": "81f2fc5b0d0cf4696146f00f837596d10b92dead"
            },
            {
              "fixed": "7ef82863d42261817a6394c6c881bd6757a70f16"
            },
            {
              "fixed": "53d32735d77ab56cc3fc7bd53a7d099418f19be1"
            },
            {
              "fixed": "f0a83d0a4b7c127d32ac06d607a9214937716129"
            },
            {
              "fixed": "35f1943d242e1b9f0b6e91c0c93bfb293a9f8224"
            },
            {
              "fixed": "baed0d9ba91d4f390da12d5039128ee897253d60"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.15.0"
            },
            {
              "fixed": "5.10.252"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.202"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.165"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.128"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.75"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.16"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "6.19.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43233.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_h323: fix OOB read in decode_choice()\n\nIn decode_choice(), the boundary check before get_len() uses the\nvariable `len`, which is still 0 from its initialization at the top of\nthe function:\n\n    unsigned int type, ext, len = 0;\n    ...\n    if (ext || (son-\u003eattr \u0026 OPEN)) {\n        BYTE_ALIGN(bs);\n        if (nf_h323_error_boundary(bs, len, 0))  /* len is 0 here */\n            return H323_ERROR_BOUND;\n        len = get_len(bs);                        /* OOB read */\n\nWhen the bitstream is exactly consumed (bs-\u003ecur == bs-\u003eend), the check\nnf_h323_error_boundary(bs, 0, 0) evaluates to (bs-\u003ecur + 0 \u003e bs-\u003eend),\nwhich is false.  The subsequent get_len() call then dereferences\n*bs-\u003ecur++, reading 1 byte past the end of the buffer.  If that byte\nhas bit 7 set, get_len() reads a second byte as well.\n\nThis can be triggered remotely by sending a crafted Q.931 SETUP message\nwith a User-User Information Element containing exactly 2 bytes of\nPER-encoded data ({0x08, 0x00}) to port 1720 through a firewall with\nthe nf_conntrack_h323 helper active.  The decoder fully consumes the\nPER buffer before reaching this code path, resulting in a 1-2 byte\nheap-buffer-overflow read confirmed by AddressSanitizer.\n\nFix this by checking for 2 bytes (the maximum that get_len() may read)\ninstead of the uninitialized `len`.  This matches the pattern used at\nevery other get_len() call site in the same file, where the caller\nchecks for 2 bytes of available data before calling get_len().",
  "id": "CVE-2026-43233",
  "modified": "2026-07-08T05:38:17.090301492Z",
  "published": "2026-05-06T11:28:29.565Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2a3aac4205e7d2f1aca2e3827de8cdd517d36c4a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/35f1943d242e1b9f0b6e91c0c93bfb293a9f8224"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/53d32735d77ab56cc3fc7bd53a7d099418f19be1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7ef82863d42261817a6394c6c881bd6757a70f16"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/81f2fc5b0d0cf4696146f00f837596d10b92dead"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/baed0d9ba91d4f390da12d5039128ee897253d60"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bcb50aa0b8f2b74a9fe5a1c7bee6f2657a288041"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f0a83d0a4b7c127d32ac06d607a9214937716129"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43233.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43233"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "netfilter: nf_conntrack_h323: fix OOB read in decode_choice()"
}