Medium Denial of service

CVE-2026-10668 — Host-triggerable control-endpoint wedge (DoS) in Nuvoton NuMaker HSUSBD UDC driver

The Nuvoton NuMaker HSUSBD USB device-controller driver (drivers/usb/udc/udc_numaker.c) armed the control Data IN stage unconditionally (base->CEPTXCNT = len in numaker_hsusbd_ep_trigger). Because the HSUSBD hardware cannot disarm a control Data IN already armed for a previous transfer, a USB host that cancels an in-flight control transfer (timeout) and then issues a new SETUP packet can drive the driver out of sync: stale data may be transmitted in the new transfer and the control endpoint can become permanently stuck NAK'ing every subsequent control transfer. A malicious or buggy host (physical/adjacent attacker driving the bus) can repeatedly cancel-and-re-SETUP to wedge the device's USB control endpoint, denying service to the device's USB function (the device stops enumerating/responding on the control pipe) until a USB reset or re-plug. The flaw is an availability-only denial of service; the FIFO copy loops (bounded by net_buf length and the hardware BUFFULL flag) and the net_buf lifecycle are independent of the arming desync, so there is no out-of-bounds access, use-after-free, or information leak. The fix monitors the IN-token and new-SETUP events (k_event) and only arms control Data IN when an IN token is present and no new SETUP has arrived, cancelling the current transfer on a new SETUP. Affects boards using the Nuvoton NuMaker HSUSBD controller (CONFIG_UDC_NUMAKER with DT_HAS_NUVOTON_NUMAKER_HSUSBD_ENABLED); shipped in v4.4.0.

Published Jul 12, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: zephyr

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Zephyrproject

Zephyr

CVSS base

4.6

Medium · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — github.com (NIST National Vulnerability Database)
Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Zephyrproject Zephyr).
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes matching the vulnerability class (denial of service), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Zephyrproject	Zephyr	≥ 4.4.0 and ≤ 4.4.1	Vulnerable	NIST National Vulnerability Database
Zephyrproject	Zephyr	≥ 4.4.0 and < 4.5.0	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Physical

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
4.6	CVSS 3.1	Medium	0.9	3.6	nvd@nist.gov via NIST National Vulnerability Database
2.4	CVSS 3.1	Low	0.9	1.4	vulnerabilities@zephyrproject.org via NIST National Vulnerability Database
2.4	CVSS 3.1	Low	—	—	zephyr via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov)

Scoring entities (NIST, CNA, ADP) score independently; each score is shown with its origin. For prioritization we use 4.6 (NVD (NIST)) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-400 · Uncontrolled Resource Consumption

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Track CPU/memory spikes and availability drops correlated with request patterns.

endpoint telemetry (EDR)resource metrics

Timeline

What happened to this CVE, newest first.

2026
Affected products added · zephyrproject/zephyr
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
Fix documented
Oct 15, 2026 · NIST National Vulnerability Database
CVSS changed · 4.6
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Jul 12, 2026 · zephyr

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

2 on the record

github.com/zephyrproject-rtos/zephyr/commit/48e003326873e8bbc0ee4b67334e0dd8b5fb
Patch, patch, NIST National Vulnerability Database
github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-rm28-x84j-4qrx
Patch, Vendor Advisory, NIST National Vulnerability Database

Elsewhere on this site

Zephyrproject
every CVE for this vendor

Denial of service
same class

CWE-400
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-75083 Integer underflow of the radio-reported frame length causes an out-of-bounds write in the NXP KW41Z IEEE 802.15.4 driver 1d
Medium CVE-2026-75085 Out-of-bounds read from received-frame length underflow in the STM32WBA IEEE 802.15.4 driver 1d
Medium CVE-2026-75084 Out-of-bounds write in the TI CC1200 IEEE 802.15.4 driver from an unvalidated radio-supplied packet length 1d
High CVE-2026-19673 Out-of-bounds read and net_buf length underflow in Zephyr Ethernet L2 when parsing a truncated VLAN header 1d
Medium CVE-2026-19940 Bluetooth HFP AG reuses a connection slot while a delayable work item is still armed, corrupting kernel timeout bookkeeping 2d
Medium CVE-2026-19939 Bluetooth Classic AVDTP: stale timeout work on signalling-channel disconnect leads to kernel timeout-list corruption 2d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-10668 is "Host-triggerable control-endpoint wedge (DoS) in Nuvoton NuMaker HSUSBD UDC driver", rated Medium. It affects Zephyr (Zephyrproject); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.6 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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