VulnerabilityPublished 13 Nov 2026

CVE-2026-16664: mcu-tools mcuboot · Bounds

Affects mcu-tools mcubootSource CVE Database V5

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Not known to be exploited · CVSS 5.1 Medium.

Data as of 13 Nov 2026, 01:45 UTC

CVSS 3.1 base score

5.1Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (zephyr)	CVSS 3.1	5.1

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

Attack Vector: Local
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
mcu-toolsmcuboot	Affected >=2.0.0	Fixed in–
GitHubmcuboot`pkg:github/mcuboot`Other threats	Affected >=2.0.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available that rejects out-of-range image indices (img_num >= MCUBOOT_IMAGE_NUMBER) before the slot lookup in the off == 0 packet processing. Additionally, bounds checking should be implemented in __flash_area_ids_for_slot() for defense in depth. Users should apply the official patch or update to a fixed version once released. Until then, restricting access to the serial/SMP recovery console can reduce risk.

Description

CVE-2026-16664 is a vulnerability in MCUboot's Zephyr serial-recovery upload handler that allows an out-of-bounds read on a static array due to lack of range checking on a host-supplied image index. This can cause a denial of service via a bus/hard fault or potentially allow unauthorized erase/write operations on non-image partitions. The flaw affects the default non-direct upload path on the Zephyr port with array-backed slot layout and impacts versions from 2.0.0 onward. The vulnerability is exploitable by anyone with access to the unauthenticated serial/SMP recovery console. A fix involves rejecting out-of-range image indices before slot lookup and adding bounds checks in the slot indexing function.

Impact

An attacker with access to the unauthenticated serial/SMP recovery console can supply out-of-range image indices causing out-of-bounds reads on a static array. This can lead to a denial of service via a bus/hard fault in the bootloader during recovery. In some cases, it may allow unauthorized erase/write operations on partitions outside the intended image set, potentially compromising system integrity. There is no information disclosure as the attacker-supplied value is never echoed back. The impact is limited to integrity and availability during recovery operations.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Nov 2026, 00:52 UTC

Technical details

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