VulnerabilityPublished 13 Nov 2026

CVE-2026-127928: mcu-tools mcuboot · Info-leak

Affects mcu-tools mcubootSource CVE Database V5

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Not known to be exploited · CVSS 2.0 Low : upgrade to 2.5.0 when convenient.

Data as of 13 Nov 2026, 01:45 UTC

CVSS 3.1 base score

2.0Low

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	2.0

Patch: Available – fixed in 2.5.0

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

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

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

Attack Vector: Physical: The attack requires the attacker to physically touch or manipulate the vulnerable component. Physical interaction may be brief or persistent.
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within 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 >=1.9.0 <2.5.0	Fixed in 2.5.0
GitHubmcuboot`pkg:github/mcuboot`Other threats	Affected >=1.9.0 <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 that properly zeroizes sensitive key material before function return paths. Users should upgrade to version 2.5.0 or later to remediate this vulnerability. No other mitigation is indicated since exploitation requires local memory-read capability.

Description

CVE-2026-127928 is an information leak vulnerability in MCUboot's encrypted image support combined with serial recovery. The vulnerability arises because the plaintext AES image key remains in stack memory after certain functions return, due to missing zeroization of sensitive data structures. An attacker with the ability to read device RAM, for example via a debug port, could recover the AES key and decrypt the protected firmware image. The device's long-term private decryption key is not exposed. Exploitation requires local memory-read access; no remote or protocol-based memory disclosure is known. The issue affects MCUboot versions from 1.9.0 up to but not including 2.5.0 and is fixed in version 2.5.0.

Impact

The vulnerability allows an attacker with local memory-read access to recover the plaintext AES key used to encrypt firmware images. This compromises the confidentiality of the encrypted firmware image, potentially allowing the attacker to decrypt and analyze or modify the firmware. However, the device's long-term private decryption key is not exposed, and no remote or protocol-based memory disclosure is known. The overall impact is limited by the requirement for local memory access and the lack of integrity or availability impact.

Summary

In MCUboot's serial-recovery encrypted-image support, the functions decrypt_image_inplace() and boot_image_validate_encrypted() use a stack-local struct boot_status containing the plaintext per-image AES key in its enckey[] field. These functions do not clear this sensitive structure before returning, leaving the AES key in dead stack memory. Additionally, error paths in decrypt_image_inplace() and boot_image_validate_encrypted() skip zeroization of the expanded AES key context, further exposing sensitive key material on the stack. This vulnerability occurs when encrypted images are uploaded or queried via the serial recovery protocol. An attacker capable of reading device RAM (e.g., through a debug interface or retained RAM) can recover the AES key, compromising the confidentiality of the encrypted firmware image. The device's long-term private decryption key remains protected. The flaw affects MCUboot versions >=1.9.0 and <2.5.0 and is fixed in 2.5.0.

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What to do

Affected software

Description

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

Technical details

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