Zephyr · Zephyr · CVE-2026-19185
**Name of the Vulnerable Software and Affected Versions**
Zephyr (affected versions not specified)
**Description**
In CONFIG USERSPACE builds, the system-call verifier for `i3c do ccc()` in drivers/i3c/i3c handlers.c fails to validate per-target data buffers within the `i3c ccc target payload` structure. Specifically, the data pointer and `data len` are not processed through `K SYSCALL MEMORY()` before being passed to `z impl i3c do ccc()` and the controller driver. Additionally, the verifier uses the caller's live structure instead of a snapshot, allowing a second user thread to modify validated fields between the check and the driver's execution. An unprivileged user-mode thread with access to the I3C controller device object can provide an arbitrary kernel address as a target payload data pointer. This allows a read CCC to write bus-received bytes into an attacker-chosen kernel address or a write CCC to transmit kernel memory onto the I3C bus, leading to out-of-bounds kernel write and kernel memory disclosure, which can result in privilege escalation to supervisor level.
**Recommendations**
At the moment, there is no information about a newer version that contains a fix for this vulnerability.