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Response snapshot Nov 4, 2026, 06:36 UTC

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VulnerabilityCVE-2026-19669

The user-mode syscall verifiers z_vrfy_fuel_gauge_get_props() and z_vrfy_fuel_gauge_set_props() in drivers/fuel_gauge/fuel_gauge_syscall_handlers.c declared two variable-length...

The user-mode syscall verifiers z_vrfy_fuel_gauge_get_props() and z_vrfy_fuel_gauge_set_props() in drivers/fuel_gauge/fuel_gauge_syscall_handlers.

At a glance

Exploited
Not known
Severity
7.8 High (CVSS 3.1)
Chance of exploitation
0.2% in the next 30 days
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-19669 (opens a new tab)

What happened

The user-mode syscall verifiers z_vrfy_fuel_gauge_get_props() and z_vrfy_fuel_gauge_set_props() in drivers/fuel_gauge/fuel_gauge_syscall_handlers.c declared two variable-length arrays, union fuel_gauge_prop_val k_vals[len] and fuel_gauge_prop_t k_props[len], sized directly by the caller-supplied len argument.

len is an unvalidated size_t taken straight from the syscall ABI, and the VLAs were allocated before any check at all — including before the K_SYSCALL_DRIVER_FUEL_GAUGE() object-permission check. The subsequent k_usermode_from_copy() calls validated only that the user source buffer was readable; the kernel destination was never bounds-checked, since it was sized by the same attacker-chosen len.

Any thread running in user mode with CONFIG_USERSPACE enabled can invoke fuel_gauge_get_props() or fuel_gauge_set_props() with a large len. This first displaces the supervisor stack pointer by an arbitrary attacker-chosen amount — Zephyr does not build with stack-clash probing, so the displacement itself does not fault, and the nested calls made by the verifier then write frames below the privileged stack.

If the caller has been granted access to a fuel-gauge device object, the memcpy inside k_usermode_from_copy() additionally writes len * sizeof(union fuel_gauge_prop_val) bytes of fully attacker-controlled data starting well below the stack base. CONFIG_PRIVILEGED_STACK_SIZE defaults to 1024 bytes, so a len of roughly 170 already exhausts it.

Continue reading

The result is an out-of-bounds write in supervisor mode with attacker-controlled length and, on the permitted path, attacker-controlled content — a break out of the user-mode sandbox into kernel memory, leading to kernel code execution or a system crash. A stack guard region does not contain it, because the copy begins below the guard and walks upward, corrupting unprotected memory before the guard is reached.

The fix removes the kernel-side copies entirely and validates the caller's arrays in place with K_SYSCALL_MEMORY_ARRAY_READ() / K_SYSCALL_MEMORY_ARRAY_WRITE(), which also handle the len * size multiplication overflow; this is safe because neither fuel_gauge_prop_t nor union fuel_gauge_prop_val contains embedded pointers.

Scores and how they were measured

CVSS base severity

7.8

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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

0.2%

Scored Percentile 7.2%

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.

Sources

  1. Primary source

    NVD CVE-2026-19669 (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

  5. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-19669, 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). The user-mode syscall verifiers z_vrfy_fuel_gauge_get_props() and z_vrfy_fuel_gauge_set_props() in drivers/fuel_gauge/fuel_gauge_syscall_handlers.c declared two variable-length... (CVE-2026-19669). https://kevwire.com/record/CVE-2026-19669

MLA

"The user-mode syscall verifiers z_vrfy_fuel_gauge_get_props() and z_vrfy_fuel_gauge_set_props() in drivers/fuel_gauge/fuel_gauge_syscall_handlers.c declared two variable-length... (CVE-2026-19669)." KEVWire, 4 Nov. 2026, kevwire.com/record/CVE-2026-19669.

Chicago

KEVWire. "The user-mode syscall verifiers z_vrfy_fuel_gauge_get_props() and z_vrfy_fuel_gauge_set_props() in drivers/fuel_gauge/fuel_gauge_syscall_handlers.c declared two variable-length... (CVE-2026-19669)." Last modified November 4, 2026. https://kevwire.com/record/CVE-2026-19669.

Evidence summary (plain text)

The user-mode syscall verifiers z_vrfy_fuel_gauge_get_props() and z_vrfy_fuel_gauge_set_props() in drivers/fuel_gauge/fuel_gauge_syscall_handlers.c declared two variable-length... (Oct 11, 2026).
The user-mode syscall verifiers z_vrfy_fuel_gauge_get_props() and z_vrfy_fuel_gauge_set_props() in drivers/fuel_gauge/fuel_gauge_syscall_handlers.c declared two variable-length arrays, union fuel_gauge_prop_val k_vals[len] and fuel_gauge_prop_t k_props[len], sized directly by the caller-supplied len argument. len is an unvalidated size_t taken straight from the syscall ABI, and the VLAs were allocated before any check at all — including before the K_SYSCALL_DRIVER_FUEL_GAUGE() object-permission check.
CVSS 7.8 (version 3.1; evidence as of Nov 4, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-19669).
EPSS 0.2% for the following 30 days, scored Nov 3, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-19669&date=2026-11-03).
Sources:
NVD CVE-2026-19669: https://nvd.nist.gov/vuln/detail/CVE-2026-19669
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-2026-19669&date=2026-11-03
Record ID: CVE-2026-19669.
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: 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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