Vulnerability-Lookup

CVE-2026-13216 (GCVE-0-2026-13216)

Vulnerability from cvelistv5 – Published: 2026-08-25 16:05 – Updated: 2026-08-25 19:41

Title

Out-of-bounds stack write in Zephyr virtio PCI driver from unvalidated device-supplied capability length

Summary

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. The 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. The 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. The 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.

Severity

6.1 (Medium)


                        
                          CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-25 19:41 UTC

CWE

CWE-787 - bounds

Assigner

zephyr mitre root

References

2 references

URL	Tags
https://github.com/zephyrproject-rtos/zephyr/comm…	patch
https://github.com/zephyrproject-rtos/zephyr/secu…

Impacted products

1 product

Vendor	Product	Version	CPE status
zephyrproject	zephyr	Affected: 4.2.0 , < 4.4.2 (semver)	guessed

Show details on NVD website

JSON

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FKIE_CVE-2026-13216

Vulnerability from fkie_nvd - Published: 2026-08-25 17:17 - Updated: 2026-08-26 16:59

Severity

6.1 (Medium) - CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Summary

References

	URL	Tags
	vulnerabilities@zephyrproject.org	https://github.com/zephyrproject-rtos/zephyr/commit/d98dacee24ad10c972d3b7281c9009d82ed351c9
	vulnerabilities@zephyrproject.org	https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-qrh3-4mvv-w667

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "defaultStatus": "unaffected",
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          ],
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            }
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-13216 (GCVE-0-2026-13216)

FKIE_CVE-2026-13216

Tags

Sightings

Nomenclature