CVE-2026-46314
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk5th percentile - higher than 5% of all known CVEs
Summary
In the Linux kernel, a vulnerability in the DRM V3D driver allows a local user to trigger an infinite loop in kernel context. By crafting an empty multisync extension with a self-referential list pointer, the existing duplicate-extension guard is bypassed, causing the calling thread to block indefinitely and pegging a CPU core.
Risk Assessment
A local user can perform a denial-of-service (DoS) attack on the system, causing a kernel thread to hang and permanently occupy one CPU core, leading to performance degradation or preventing other processes from running.
Recommendation
Immediately update the Linux kernel to a version containing the fix that rejects empty multisync extensions (with zero in_sync_count and out_sync_count). For production systems, apply the security patch from your distributor.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: drm/v3d: Reject empty multisync extension to prevent infinite loop v3d_get_extensions() walks a userspace-provided singly-linked list of ioctl extensions without any bound on the chain length. A local user can craft a self-referential extension (ext->next == &ext) with zero in_sync_count and out_sync_count, which bypasses the existing duplicate- extension guard: if (se->in_sync_count || se->out_sync_count) return -EINVAL; The guard never fires because v3d_get_multisync_post_deps() returns immediately when count is zero, leaving both fields at zero on every iteration. The result is an infinite loop in kernel context, blocking the calling thread and pegging a CPU core indefinitely. Fix this by rejecting a multisync extension where both in_sync_count and out_sync_count are zero in v3d_get_multisync_submit_deps(). An empty multisync carries no synchronization information and serves no useful purpose, so returning -EINVAL for such an extension is the correct defense against this attack vector.