Is there a public exploit for CVE-2026-16659?

No public exploit for CVE-2026-16659 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-2026-16659?

CVE-2026-16659 scores CVSS 4 (v3.1), rated medium.

What does CVE-2026-16659 affect?

CVE-2026-16659 affects mcu-tools mcuboot.

4.0 Medium

MCUboot's serial-recovery image-upload handler bsupload() in boot/bootserial/src/bootserial.c declares const struct flasharea fap = NULL…

CVE-2026-16659

MCUboot's serial-recovery image-upload handler bsupload() in boot/bootserial/src/bootserial.c declares const struct flasharea fap = NULL and assigns it only via flashareaopen() part-way through the function. Two early validation failures (goto outinvaliddata) — a CBOR map that fails to decode, or an upload packet missing the off/data members — branch past the open while fap is still NULL, then fall into the shared epilogue. In MCUBOOTENCIMAGES builds that epilogue unconditionally calls boothandleencfw(fap), which reaches bootimageloadheader() and flasharearead() and dereferences the NULL flasharea. The defect is reachable pre-authentication: the trigger is the very first serial-recovery upload command carrying a malformed payload. The guarding conditions are default-true on a fresh recovery session — imgnum, curroff and imgsize are zero-initialized statics, so curroff == imgsize and the primary-slot test both hold. It requires a non-default build: encrypted images (MCUBOOTENCIMAGES / Zephyr CONFIGBOOTENCRYPTIMAGE) together with an active serial-recovery transport, on the Zephyr or Mynewt port (the two that build both boot/bootserial/src/bootserial.c and bootserialencryption.c with…

Assessment

CVSS: 4 (v3.1)
Severity: Medium
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:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

At the source

EUVD (ENISA)

References

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