{"cve":{"cve_id":"CVE-2026-13212","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.00223,"epss_percentile":0.1202,"epss_as_of":"2026-10-15","description":"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).\n\nBecause 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.\n\nThe 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.","published_at":"2026-08-24T15:43:37.762000Z","last_modified_at":"2026-10-12T15:10:00.207000Z","cvss_v3_score":8.8,"cvss_v3_vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_v3_severity":"HIGH","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":"none","ssvc_automatable":false,"ssvc_technical_impact":"total","cwes":["CWE-129"],"nvd_references":["https://github.com/zephyrproject-rtos/zephyr/commit/fe47dbca080957c425383cc1d5bdc7d48a41d4a5","https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-7884-373w-qqhx"],"vuln_status":"Awaiting Analysis","trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-08-24T16:42:27.516315Z","updated_at":"2026-10-13T23:59:09.159740Z"},"effective_severity":"HIGH","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"A","value_label":"Adjacent"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"zephyrproject","vendor_name":"zephyrproject","product_slug":"zephyr","product_name":"zephyr","version_start":"4.2.0","version_start_inclusive":true,"version_end":"4.4.2","version_end_inclusive":false,"cpe23_uri":"cve5:zephyrproject:zephyr:4.2.0:4.4.2"}],"exploit_refs":[],"news":[],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/fe47dbca080957c425383cc1d5bdc7d48a41d4a5","source_type":"PATCH","tags":["patch"]},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-7884-373w-qqhx","source_type":"VENDOR_ADVISORY","tags":["advisory"]}],"timeline":[{"type":"published","at":"2026-08-24T15:43:37.762000Z","label":"CVE published","source":null},{"type":"ssvc_changed","at":"2026-08-24T21:37:20.298186Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-08-24T21:37:20.298186Z","label":"SSVC decision revised","source":"vulnrichment"},{"type":"ssvc_changed","at":"2026-08-24T21:37:20.298186Z","label":"SSVC decision revised","source":"vulnrichment"}]}