CVE-2026-89724

Received Received - Intake

Heap Buffer Overflow in Linux Kernel V4L2 FWHT Encoder

Publication date: 2026-09-11

Last updated on: 2026-09-11

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: media: vicodec: fix out-of-bounds write in FWHT encoder vidioc_s_fmt_vid_out() sizes the encoder CAPTURE buffer from the compressed descriptor pixfmt_fwht, whose sizeimage_mult is 3: coded_w * coded_h * 3 + sizeof(struct fwht_cframe_hdr). fwht_encode_frame() encodes one plane per component, and an incompressible plane takes the FWHT_FRAME_UNENCODED path in encode_plane(), copying the plane verbatim. For a 4-component pixel format all four planes are full resolution (width_div == height_div == 1), so a frame that forces every plane through the unencoded fallback writes sizeof(struct fwht_cframe_hdr) + 4 * coded_w * coded_h bytes, overrunning the plane by coded_w * coded_h, which can result in corruption of adjacent kernel heap memory. Bump pixfmt_fwht.sizeimage_mult from 3 to 4, matching the largest components_num among the supported raw formats, so the capture buffer is always large enough for the unencoded fallback.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-09-11

Last Modified

2026-09-11

Generated

2026-09-12

AI Q&A

2026-09-12

EPSS Evaluated

N/A

NVD

CVE-2026-89724

EUVD

EUVD-2026-76636

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	to 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves an out-of-bounds write in the FWHT encoder of the vicodec media driver. When processing a 4-component pixel format, the encoder copies uncompressed planes verbatim, leading to buffer overflow. The issue arises because the capture buffer size is calculated incorrectly, causing adjacent kernel heap memory corruption.

Detection Guidance

This vulnerability is specific to the Linux kernel's vicodec media driver and requires kernel-level access to detect. No direct network detection commands exist. Check kernel logs for media-related errors or crashes using dmesg | grep vicodec or journalctl -k | grep vicodec.

Impact Analysis

This vulnerability could allow an attacker with local access to corrupt kernel memory, potentially leading to system crashes, privilege escalation, or arbitrary code execution. It may also enable denial-of-service conditions or data leaks depending on the affected system's configuration.

Mitigation Strategies

Update your Linux kernel to the latest stable version where this vulnerability is patched. If using a distribution kernel, apply vendor-provided updates immediately. Reboot the system after updating to ensure the patched kernel is active.

Hi! I’m here to help you understand CVE-2026-89724. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70