Is there a public exploit for CVE-2026-128091?

No public exploit for CVE-2026-128091 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-128091?

CVE-2026-128091 scores CVSS 2 (v3.1), rated low.

What does CVE-2026-128091 affect?

CVE-2026-128091 affects mcu-tools mcuboot.

2.0 Low

When MCUboot is built with the TinyCrypt crypto backend (MCUBOOTUSETINYCRYPT), bootutilaesctrdrop() in…

CVE-2026-128091

When MCUboot is built with the TinyCrypt crypto backend (MCUBOOTUSETINYCRYPT), bootutilaesctrdrop() in boot/bootutil/include/bootutil/crypto/aesctrtinycrypt.h was an empty stub. The AES-CTR context for this backend is the fully expanded AES-128 key schedule (struct tcaeskeyschedstruct). Generic code relies on this hook to release and clear key state, so with TinyCrypt nothing was cleared. The mbedTLS and PSA backends do free or destroy their key state here. As a result, bootstateclear(), which bootgo() calls before handing off to the application, left the image's AES content-encryption key schedule in the static bootdata state. This is the case after an encrypted upgrade in single-image builds, where bootenczeroize() is not called. bootdecryptkey() likewise left the ECIES-derived key-encryption key schedule on the stack. The affected build uses MCUBOOTENCIMAGES with TinyCrypt, which is the default ECDSA and Ed25519 backend in the Zephyr port. The first AES-128 round key equals the cipher key, so anyone who can read the leftover bootloader RAM after boot can recover the image content key and decrypt that encrypted image. That includes a physical attacker with debug or RAM access,…

Assessment

CVSS: 2 (v3.1)
Severity: Low
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 13 November 2026
Last updated: 13 November 2026
Affected: mcu-tools · mcuboot
Assigner: zephyr

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

At the source

EUVD (ENISA)

References

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