AES image key left on the stack after serial-recovery encrypted-image handling in MCUboot

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-127928
StatePUBLISHED
Assignerzephyr
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-13 02:18:56 UTC
Updated2026-11-13 02:18:56 UTC
DescriptionIn MCUboot's serial-recovery encrypted-image support (boot/boot_serial/src/boot_serial_encryption.c), decrypt_image_inplace() and boot_image_validate_encrypted() each keep a stack-local struct boot_status. boot_enc_load() writes the plaintext per-image AES key into its enckey[] field. Neither function cleared this structure before returning. In addition, a decrypt failure inside the per-sector loop of decrypt_image_inplace() returned early and skipped the total_out: cleanup, which left the expanded AES key context (enc_data) on the stack as well. The error paths of boot_image_validate_encrypted() similarly skipped boot_enc_zeroize(). The affected code is built when encrypted images (MCUBOOT_ENC_IMAGES, Zephyr CONFIG_BOOT_ENCRYPT_IMAGE) are combined with serial recovery. It runs when an encrypted image is uploaded to the primary slot over the recovery protocol, and when the image list or state is queried while an encrypted image is in the secondary slot. After these functions return, the image's AES content key remains in dead stack memory. An attacker who can later read device RAM, for example through a debug port or retained RAM, can recover it. This weakens the confidentiality of image-encryption keys within the bootloader trust boundary. A recovered key exposes the plaintext of the encrypted firmware image it protects. The device's long-term private decryption key is not exposed. No remote or recovery-protocol channel that returns this memory is known, so exploitation requires a separate memory-read capability.

Risk And Classification

Primary CVSS: v3.1 2 LOW from [email protected]

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

Problem Types: CWE-226 | CWE-226 info-leak

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary2LOWCVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1CNACVSS2LOWCVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mcu-tools Mcuboot affected 1.9.0 2.5.0 semver Not specified

References

ReferenceSourceLinkTags
github.com/mcu-tools/mcuboot/security/advisories/GHSA-hqmg-jwp9-8cf8 [email protected] github.com
github.com/mcu-tools/mcuboot/commit/411949f830724617fbc08b9b32f0a45ba0c8... [email protected] github.com
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