CVE-2026-64264

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

fuse-uring: fix EFAULT clobber in fuse_uring_commit

copy_from_user() returns the number of bytes not copied as an unsigned

residual on failure (1..sizeof(struct fuse_out_header)). fuse_uring_commit

stores that residual in ssize_t err, sets req->out.h.error to -EFAULT,

then jumps to out: with err still holding the positive residual.

err = copy_from_user(&req->out.h, &ent->headers->in_out,

sizeof(req->out.h));

if (err) {

req->out.h.error = -EFAULT;

goto out; /* err is the positive residual */

}

...

out:

fuse_uring_req_end(ent, req, err);

fuse_uring_req_end() then runs

if (error)

req->out.h.error = error;

which overwrites the just-assigned -EFAULT with the positive residual.

FUSE callers such as fuse_simple_request() test err < 0 to detect

failure, so the positive value is interpreted as success and the

caller proceeds with an

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References