VulnerabilityPublished 13 Nov 2026

CVE-2026-16659: mcu-tools mcuboot · Memory-safety

Affects mcu-tools mcubootSource CVE Database V5

Compare

Not known to be exploited · CVSS 4.0 Medium : upgrade to 2.5.0 when convenient.

Data as of 13 Nov 2026, 01:45 UTC

CVSS 3.1 base score

4.0Medium

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	4.0

Patch: Available – fixed in 2.5.0

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

Attack Vector: Local
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
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: None: There is no loss of integrity within 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

Upgrade mcu-tools mcuboot to 2.5.0.

Affected software

Product	Affected	Fixed in
mcu-toolsmcuboot	Affected >=2.0.0 <2.5.0	Fixed in 2.5.0
GitHubmcuboot`pkg:github/mcuboot`Other threats	Affected >=2.0.0 <2.5.0	Fixed in 2.5.0

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 in MCUboot version 2.5.0. Users should upgrade to this version or later to remediate the vulnerability. No additional mitigation is required as the issue is resolved by the official patch.

Description

CVE-2026-16659 is a memory-safety vulnerability in MCUboot's serial-recovery image-upload handler affecting certain encrypted image builds on Zephyr and Mynewt ports. The flaw occurs when early validation failures cause a NULL pointer dereference in the bootloader's recovery code, leading to a transient denial of service. This issue does not allow memory corruption or information disclosure and only affects non-default builds with encrypted images and serial recovery enabled. The vulnerability is fixed in MCUboot version 2.5.0.

Impact

The vulnerability causes a transient denial of service of the bootloader during recovery by dereferencing a NULL pointer. There is no memory corruption or information leak, and image authentication remains intact. The severity of the fault depends on the platform's handling of NULL pointers—some may return an error and continue execution, while others may experience a hard fault. Since serial recovery is unauthenticated and already allows writing to the secondary slot, the impact is limited to a low-value denial of service.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

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

Technical details

References

Community reviews

Related threats