CVE-2026-13212 (GCVE-0-2026-13212)
Vulnerability from cvelistv5 – Published: 2026-08-24 15:43 – Updated: 2026-11-04 04:59
VLAI
EPSS
VEX
Title
Zephyr virtio driver calls an arbitrary function pointer from an out-of-range used-ring descriptor id
Summary
The Zephyr virtio driver does not validate the descriptor-chain head id that the virtio device writes into the used ring. In virtio_isr() (drivers/virtio/virtio_common.c), the device-written vq->used->ring[idx].id is used directly as an index into vq->recv_cbs[] and vq->desc[], which are both allocated with exactly vq->num entries. recv_cbs[] holds {cb, opaque} callback entries, and the indexed callback pointer is then invoked as cbe.cb(cbe.opaque, used_len).
Because the id is consumed as a 16-bit value with no bound check, a malicious or compromised virtio backend (an untrusted hypervisor, or an untrusted hardware/peer-processor virtio device on a PCI or MMIO transport) can supply an id far beyond vq->num. This causes an out-of-bounds read of a {function pointer, argument} pair from heap memory beyond recv_cbs[], after which the driver calls that attacker-shaped pointer in the guest's interrupt context. No guest privileges or user interaction are required; the backend triggers it by writing the shared used ring and raising the queue interrupt.
The result is an arbitrary / attacker-influenced function-pointer call in the Zephyr guest, i.e. a control-flow-hijack primitive that can lead to code execution or, at minimum, a reliable crash. The fix rejects any used-ring id >= vq->num before indexing recv_cbs[]/desc[] or invoking the callback. This affects builds using CONFIG_VIRTIO with the PCI or MMIO transport.
Severity
8.8 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-24 20:19 UTC
CWE
- CWE-129 - memory-safety
Assigner
zephyr
CNA
References
2 references
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| zephyrproject | zephyr |
Affected:
4.2.0 , < 4.3.2
(semver)
Affected: 4.4.0 , < 4.4.2 (semver) |
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