media: vicodec: fix out-of-bounds write in FWHT encoder

Overview

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.

Affected

• Linux >= 16ecf6dff97ce0194a7126e26159492668d47a7e < f7ae26c100a6c26c2a166d2c41e73188067b36bd
• Linux >= 16ecf6dff97ce0194a7126e26159492668d47a7e < 6ea647e76c44387d5c1c635df4604c2154d9060e
• Linux >= 16ecf6dff97ce0194a7126e26159492668d47a7e < d40838a63f2bd6a3df0a6cdd8ff1d5c6366e8fff
• Linux >= 16ecf6dff97ce0194a7126e26159492668d47a7e < e21cccc29b840930cd9dcfdf1139658063a681af
• Linux >= 16ecf6dff97ce0194a7126e26159492668d47a7e < 84cfebf7f4229d748cca8eb9c4e1f1c4099d3ab7
• Linux >= 16ecf6dff97ce0194a7126e26159492668d47a7e < 8c14472431e27f13661d0db9d837156eaced0ecb
• Linux >= 16ecf6dff97ce0194a7126e26159492668d47a7e < b95315ffc66b39856396c1043618bb4e4d5785ba
• Linux >= 16ecf6dff97ce0194a7126e26159492668d47a7e < cf4500ebf6fb57bf4ab83c3dd349a40257dbe2a9
• Linux 5.0

Remediation

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

Vendor advisories

• Red Hat VEX · Moderate · updated 2026-09-15 · vex