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VulnerabilityPublished Updated

CVE-2025-21956: Linux kernel · drm/amd/display: Assign normalized_pix_clk when color depth = 14

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 5.5 Medium · fixed in 5.4.0-1147.157~18.04.1 : update Linux kernel when convenient.

Data as of 28 Oct 2026, 11:14 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.4.0-1147.157~18.04.1, 5.4.0-1152.159~18.04.1, 5.4.0-1150.159~18.04.1 +87
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 Apr 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-84.84
Fixed in
  • 6.8.0-84.84
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1039.41
Fixed in
  • 6.8.0-1039.41
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1038.44
Fixed in
  • 6.8.0-1038.44
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threatsAffected
  • <6.11.0-1018.18~24.04.1
Fixed in
  • 6.11.0-1018.18~24.04.1
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1025.27
Fixed in
  • 6.8.0-1025.27
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1040.42
Fixed in
  • 6.8.0-1040.42

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Assign normalized_pix_clk when color depth = 14 [WHY & HOW] A warning message "WARNING: CPU: 4 PID: 459 at ... /dc_resource.c:3397 calculate_phy_pix_clks+0xef/0x100 [amdgpu]" occurs because the display_color_depth == COLOR_DEPTH_141414 is not handled. This is observed in Radeon RX 6600 XT. It is fixed by assigning pix_clk * (14 * 3) / 24 - same as the rests. Also fixes the indentation in get_norm_pix_clk. (cherry picked from commit 274a87eb389f58eddcbc5659ab0b180b37e92775)

References

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