---
id: CVE-2026-46314
title: |-
  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 b…
summary: |-
  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 b…
severity: none
published: '2026-06-08'
updated: '2026-07-07'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-46314'
references:
  - url: 'https://git.kernel.org/stable/c/309abbddeca0c12714721928a819ef45e5710998'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4fa42a249e8cd6ed17aea04e5695b6e9001f2433'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9c5164781cb388d219d8f49fa0f0b04cf86ad544'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fb44d589bf3148e13452185a6e772a7efbf2d684'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00163
epssPercentile: 0.04877
ingestedAt: '2026-07-08T12:51:00.729Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.