CVE-2026-98860 HID: bpf: cast size to ssize_t when checking hid_bpf_hw_request
A type confusion in the Linux kernel HID BPF subsystem allows hardware errors to be misinterpreted as success, potentially exposing uninitialized memory to BPF programs.
- 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-2026-98860?
CVE-2026-98860 is a vulnerability in Linux, published on 18 Oct 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:
HID: bpf: cast size to ssize_t when checking hid_bpf_hw_request
As reported by Sashiko: If a transport driver encounters a hardware error and returns a negative error code such as -EPIPE, ret is implicitly promoted to size_t when compared against size. This causes the negative error code to evaluate as a large positive number, making the (ret > size) condition true.
This silently converts the hardware error into a success return value and copies the unmodified buffer back, which could leave BPF programs operating on uninitialized or stale data.
Fix this by casting size into ssize_t to return the actual negative error code.
Which versions are affected by CVE-2026-98860?
How do I fix CVE-2026-98860?
Apply the vendor's patch.
Is CVE-2026-98860 being exploited?
There is no known exploitation of CVE-2026-98860 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-98860, DEBIAN-CVE-2026-98860, GHSA-243p-r44x-jh77, UBUNTU-CVE-2026-98860.