{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "4.2.0"
              },
              {
                "fixed": "4.4.2"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "413b789deb391d3a37d06b463288a5fe765ee57e"
            },
            {
              "fixed": "d98dacee24ad10c972d3b7281c9009d82ed351c9"
            }
          ],
          "repo": "https://github.com/zephyrproject-rtos/zephyr",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-qrh3-4mvv-w667"
  ],
  "database_specific": {
    "cna_assigner": "zephyr",
    "cwe_ids": [
      "CWE-787"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/13xxx/CVE-2026-13216.json"
  },
  "details": "The virtio PCI driver (drivers/virtio/virtio_pci.c) parses a device's PCI capability list during driver initialization. In virtio_pci_read_cap() the device-supplied capability length byte cap_len (read from PCI config space via pcie_conf_read()) was only checked with assert(tmp.cap_len == cap_struct_size). That assert resolves to __ASSERT_NO_MSG(), gated by CONFIG_ASSERT, which defaults off in production builds, so the value reached the copy logic completely unvalidated.\n\nThe length then drives a loop that copies extra capability dwords into a fixed-size stack buffer supplied by the caller. A cap_len below the 24-byte base struct virtio_pci_cap underflows the unsigned extra_data_words count to a near-SIZE_MAX value, producing an effectively unbounded stack write; a cap_len above the caller's buffer (up to 255) writes up to roughly 228 bytes of device-controlled data past the buffer. Both are out-of-bounds writes of attacker-controlled content executed in kernel mode during boot-time device probe.\n\nThe input originates from the virtio device. In the common deployment where Zephyr runs as a guest under a hypervisor, the device backend is the host, which already fully outranks the guest, so the bug yields no privilege escalation. The exploitable case is a virtio device that is untrusted relative to the Zephyr kernel — an untrusted or physical/passthrough virtio PCIe device on a bare-metal system, or a confidential-computing posture where the guest must defend against the host — where a malicious device can corrupt the kernel stack and potentially achieve code execution or a crash.\n\nThe fix replaces the compiled-out assert with a runtime range check rejecting cap_len outside [sizeof(struct virtio_pci_cap), cap_struct_size] before any arithmetic or copy.",
  "id": "CVE-2026-13216",
  "modified": "2026-08-28T11:30:21.688580321Z",
  "published": "2026-08-25T16:05:36.964Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/13xxx/CVE-2026-13216.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-qrh3-4mvv-w667"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-13216"
    },
    {
      "type": "FIX",
      "url": "https://github.com/zephyrproject-rtos/zephyr/commit/d98dacee24ad10c972d3b7281c9009d82ed351c9"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/zephyrproject-rtos/zephyr"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Out-of-bounds stack write in Zephyr virtio PCI driver from unvalidated device-supplied capability length"
}