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Response snapshot Nov 4, 2026, 07:46 UTC

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VulnerabilityCVE-2026-16511

Two RTIO syscall verifiers, in subsys/rtio/rtio_syscalls.c (subsys/rtio/rtio_handlers.c before v4.3.0), did not validate user-supplied pointers before the kernel wrote through...

Two RTIO syscall verifiers, in subsys/rtio/rtio_syscalls.c (subsys/rtio/rtio_handlers.c before v4.3.0), did not validate user-supplied pointers before the kernel wrote through them. z_vrfy_rtio_sqe_cancel() performed no validation at all.

At a glance

Exploited
Not known
Severity
8.8 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-16511 (opens a new tab)

What happened

Two RTIO syscall verifiers, in subsys/rtio/rtio_syscalls.c (subsys/rtio/rtio_handlers.c before v4.3.0), did not validate user-supplied pointers before the kernel wrote through them.

z_vrfy_rtio_sqe_cancel() performed no validation at all. It passed the caller's struct rtio_sqe pointer straight to z_impl_rtio_sqe_cancel(), which converts it with CONTAINER_OF to a struct rtio_iodev_sqe, ORs RTIO_SQE_CANCELED (BIT(3)) into its 16-bit flags field in supervisor mode, then loads its next pointer and repeats until that pointer is NULL.

The syscall takes no RTIO context argument, so it needs no object grant: any user-mode thread on a CONFIG_USERSPACE build can set that bit in a 16-bit word at an address of its choosing in kernel memory, and the kernel continues the write along whatever pointer chain it finds at the corresponding offset.

Setting chosen bits in kernel data structures, such as object permission or thread state fields, can be used to escalate privilege from user mode.

Continue reading

z_vrfy_rtio_sqe_copy_in_get_handles() validated its RTIO context and the input SQE array, but only NULL-checked the handle out-parameter before writing a kernel SQE pointer through it, with no K_SYSCALL_MEMORY_WRITE check. A user thread that holds a granted RTIO context can therefore make the kernel store a pointer value at an arbitrary address.

The fixes validate the handle out-parameter as writable, bound the cancel handle to real submission-pool storage, and require permission on the RTIO context that owns the matching pool. Without that last check a bounded handle still let any user thread cancel submissions belonging to other contexts, silently aborting their I/O. Systems built without CONFIG_USERSPACE or without CONFIG_RTIO are unaffected.

Scores and how they were measured

CVSS base severity

8.8

Version 3.1As of

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

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Sources

  1. Primary source

    NVD CVE-2026-16511 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 4). Two RTIO syscall verifiers, in subsys/rtio/rtio_syscalls.c (subsys/rtio/rtio_handlers.c before v4.3.0), did not validate user-supplied pointers before the kernel wrote through... (CVE-2026-16511). https://kevwire.com/record/CVE-2026-16511

MLA

"Two RTIO syscall verifiers, in subsys/rtio/rtio_syscalls.c (subsys/rtio/rtio_handlers.c before v4.3.0), did not validate user-supplied pointers before the kernel wrote through... (CVE-2026-16511)." KEVWire, 4 Nov. 2026, kevwire.com/record/CVE-2026-16511.

Chicago

KEVWire. "Two RTIO syscall verifiers, in subsys/rtio/rtio_syscalls.c (subsys/rtio/rtio_handlers.c before v4.3.0), did not validate user-supplied pointers before the kernel wrote through... (CVE-2026-16511)." Last modified November 4, 2026. https://kevwire.com/record/CVE-2026-16511.

Evidence summary (plain text)

Two RTIO syscall verifiers, in subsys/rtio/rtio_syscalls.c (subsys/rtio/rtio_handlers.c before v4.3.0), did not validate user-supplied pointers before the kernel wrote through... (Nov 4, 2026).
Two RTIO syscall verifiers, in subsys/rtio/rtio_syscalls.c (subsys/rtio/rtio_handlers.c before v4.3.0), did not validate user-supplied pointers before the kernel wrote through them.

z_vrfy_rtio_sqe_cancel() performed no validation at all. It passed the caller's struct rtio_sqe pointer straight to z_impl_rtio_sqe_cancel(), which converts it with CONTAINER_OF to a struct rtio_iodev_sqe, ORs RTIO_SQE_CANCELED (BIT(3)) into its 16-bit flags field in supervisor mode, then loads its next pointer and repeats until that pointer is NULL.
CVSS 8.8 (version 3.1; evidence as of Nov 4, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-16511).
Sources:
NVD CVE-2026-16511: https://nvd.nist.gov/vuln/detail/CVE-2026-16511
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-04T06:16:00.495Z&lastModEndDate=2026-11-04T07:45:55.805Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-04T05:35:57.064Z&lastModEndDate=2026-11-04T07:15:57.583Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-04T05:00:57.032Z&lastModEndDate=2026-11-04T06:35:55.811Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-16511.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 4, 2026, 07:45 UTC. Ingestion is not an independent editorial investigation.

NVD status: Awaiting Analysis. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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