CVE-2026-93079 cxl/features: Reject Get Feature count larger than the output buffer
A heap buffer overflow in the Linux kernel CXL features driver allows local attackers to execute arbitrary code or escalate privileges via crafted firmware control requests.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93079?
CVE-2026-93079 is a high-severity memory corruption vulnerability in Linux, published on 17 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:
cxl/features: Reject Get Feature count larger than the output buffer
cxlctl_get_feature() sizes its output buffer from the user's fwctl_rpc.out_len, but the device is told to write cxl_mbox_get_feat_in.count bytes into rpc_out->payload, which is a separate user-controlled value. Nothing bounds count against out_len, so a small out_len with a large count overflows the kvzalloc()'d buffer. A heap OOB write reachable from FWCTL_RPC.
Reject requests where count exceeds the available payload room, before allocating.
Which versions are affected by CVE-2026-93079?
How do I fix CVE-2026-93079?
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-2026-93079 being exploited?
There is no known exploitation of CVE-2026-93079 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-93079, DEBIAN-CVE-2026-93079, GHSA-6wmr-43p3-p5m9, UBUNTU-CVE-2026-93079.