Is there a public exploit for CVE-2026-87038?

No public exploit for CVE-2026-87038 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-2026-87038?

CVE-2026-87038 scores CVSS 7 (v3.1), rated high.

What does CVE-2026-87038 affect?

CVE-2026-87038 affects zephyrproject Zephyr.

7.0 High

The user-mode verification handler for the i3ctransfer() system call, zvrfyi3ctransfer() in drivers/i3c/i3chandlers.c, validated the…

CVE-2026-87038

The user-mode verification handler for the i3ctransfer() system call, zvrfyi3ctransfer() in drivers/i3c/i3chandlers.c, validated the caller-supplied struct i3cdevicedesc in place instead of snapshotting it. It confirmed only that the descriptor was readable by the calling thread (KSYSCALLMEMORYREAD()), read target->bus once to check it with KSYSCALLOBJ(), and then passed the caller's live pointer down. The implementation zimpli3ctransfer() re-reads target->bus from that user memory and dispatches through it as DEVICEAPIGET(i3c, target->bus)->i3cxfers(...), so the bus that was validated is not necessarily the bus that is used. DEVICEAPIGET() performs no runtime type check outside CONFIGDEVICEAPIASSERT builds. On a build with CONFIGUSERSPACE and an I3C controller driver, a user thread that has been granted an I3C device object can exploit this with a second thread in the same memory domain: one thread calls i3ctransfer() while the other rewrites the bus field of the descriptor. The window between the check and the use spans the nummsgs validation, the message-array access check, a stack VLA allocation and a memcpy() of up to 32 struct i3cmsg, so the race is repeatable and can simply…

Assessment

CVSS: 7 (v3.1)
Severity: High
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 4 November 2026
Last updated: 4 November 2026
Affected: zephyrproject · Zephyr
Assigner: zephyr

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

At the source

EUVD (ENISA)

References

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