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Response snapshot Nov 4, 2026, 06:36 UTC

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VulnerabilityCVE-2026-10667

Zephyr's dynamic kernel-object tracking (kernel/userspace/userspace.c, formerly kernel/userspace.c) maintains a doubly-linked list (obj_list) of dynamically allocated kernel...

Zephyr's dynamic kernel-object tracking (kernel/userspace/userspace.c, formerly kernel/userspace.c) maintains a doubly-linked list (obj_list) of dynamically allocated kernel objects.

At a glance

Exploited
Not known
Severity
7.8 High (CVSS 3.1)
Chance of exploitation
0.1% in the next 30 days
Sources
2 independent sources

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-10667 (opens a new tab)

What happened

Zephyr's dynamic kernel-object tracking (kernel/userspace/userspace.c, formerly kernel/userspace.c) maintains a doubly-linked list (obj_list) of dynamically allocated kernel objects.

Iteration over this list in k_object_wordlist_foreach() was performed under lists_lock using the SAFE iterator (which caches the next node), but list removal and freeing of nodes was performed under different, disjoint spinlocks: objfree_lock in k_object_free() and obj_lock in unref_check().

On an SMP system, while one CPU iterated obj_list under lists_lock, another CPU could unlink and k_free() the dyn_obj node that the iterator had cached as its next pointer, causing the iterator to dereference freed kernel memory (use-after-free / dangling list traversal).

All of the racing operations are reachable from unprivileged user-mode threads via system calls: k_object_alloc/k_object_alloc_size and k_object_release drive removals through unref_check() (under obj_lock), while k_thread_abort and thread creation drive the iteration through k_thread_perms_all_clear()/k_thread_perms_inherit() (under lists_lock).

Continue reading

A deprivileged user thread on a CONFIG_SMP + CONFIG_USERSPACE build can therefore corrupt the kernel's object-tracking structures across the userspace security boundary, yielding kernel memory corruption (potential privilege escalation) or a kernel crash (denial of service).

The fix removes objfree_lock and serializes every obj_list modification under lists_lock, including holding it across find+remove in k_object_free() and around unref_check() in k_thread_perms_clear(). Affects CONFIG_SMP+CONFIG_USERSPACE+CONFIG_DYNAMIC_OBJECTS configurations; the defect dates to the 2019 spinlockification (commit 8a3d57b6cc6, first released in v1.14.0) and shipped through v4.4.0.

Scores and how they were measured

CVSS base severity

7.8

Version 3.1As of

CVSS:3.1/AV:L/AC:H/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

0.1%

Scored Percentile 4.1%

Model and measurement source (opens a new tab)

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

Related technology

Sources

  1. Primary source

    NVD CVE-2026-10667 (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

    Vendor advisory (via NVD references) (opens a new tab)

    The vendor advisory referenced by the CVE record, for affected versions and fixes.

    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

  5. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  6. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-10667, scored 2026-11-03. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

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

APA

KEVWire. (2026, November 4). Zephyr's dynamic kernel-object tracking (kernel/userspace/userspace.c, formerly kernel/userspace.c) maintains a doubly-linked list (obj_list) of dynamically allocated kernel... (CVE-2026-10667). https://kevwire.com/record/CVE-2026-10667

MLA

"Zephyr's dynamic kernel-object tracking (kernel/userspace/userspace.c, formerly kernel/userspace.c) maintains a doubly-linked list (obj_list) of dynamically allocated kernel... (CVE-2026-10667)." KEVWire, 4 Nov. 2026, kevwire.com/record/CVE-2026-10667.

Chicago

KEVWire. "Zephyr's dynamic kernel-object tracking (kernel/userspace/userspace.c, formerly kernel/userspace.c) maintains a doubly-linked list (obj_list) of dynamically allocated kernel... (CVE-2026-10667)." Last modified November 4, 2026. https://kevwire.com/record/CVE-2026-10667.

Evidence summary (plain text)

Zephyr's dynamic kernel-object tracking (kernel/userspace/userspace.c, formerly kernel/userspace.c) maintains a doubly-linked list (obj_list) of dynamically allocated kernel... (Jul 12, 2026).
Zephyr's dynamic kernel-object tracking (kernel/userspace/userspace.c, formerly kernel/userspace.c) maintains a doubly-linked list (obj_list) of dynamically allocated kernel objects. Iteration over this list in k_object_wordlist_foreach() was performed under lists_lock using the SAFE iterator (which caches the next node), but list removal and freeing of nodes was performed under different, disjoint spinlocks: objfree_lock in k_object_free() and obj_lock in unref_check().
CVSS 7.8 (version 3.1; evidence as of Nov 4, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-10667).
EPSS 0.1% for the following 30 days, scored Nov 3, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-10667&date=2026-11-03).
Sources:
NVD CVE-2026-10667: https://nvd.nist.gov/vuln/detail/CVE-2026-10667
Vendor advisory (via NVD references): https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-9x5j-h3rh-x579
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
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-04T04:31:09.055Z&lastModEndDate=2026-11-04T06:00:55.075Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-04T03:55:55.886Z&lastModEndDate=2026-11-04T05:30:57.785Z&resultsPerPage=500&startIndex=0
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-10667&date=2026-11-03
Record ID: CVE-2026-10667.
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, 06:01 UTC. Ingestion is not an independent editorial investigation.

NVD status: Analyzed. 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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