CVE-2026-89728 i3c: renesas: Fix out-of-bounds access for newdevs mask
An out-of-bounds access in the Renesas I3C driver can cause a crash or memory corruption when the I3C bus is empty during Dynamic Address Assignment.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89728?
CVE-2026-89728 is a memory corruption vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
i3c: renesas: Fix out-of-bounds access for newdevs mask
When software initiates DAA (Dynamic Address Assignment), the controller reports the result via the NRSPQP (Normal Response Queue Port Register). The data length field of the response descriptor, which is accessible through the NRSPQP register, indicates the number of devices remaining after DAA. Consequently, when the bus is empty, this field contains the maximum number of devices supported by the controller (8 for the Renesas I3C controller).
Adjust the condition that computes the newly discovered devices bitmask to prevent an out-of-bounds when the I3C bus is empty.
Which versions are affected by CVE-2026-89728?
How do I fix CVE-2026-89728?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-89728 being exploited?
There is no known exploitation of CVE-2026-89728 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-89728, GHSA-hwqr-35ww-7c42, UBUNTU-CVE-2026-89728.