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Linux KernelOperating system · Linux

CVE-2025-21956

MEDIUM · 5.5 CVSS v3.1 Published 2025-04-01
Fix available
A fix is available. Upgrade to 5.4.292 / 5.10.236 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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)

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 4.15, < 5.4.292>= 5.5, < 5.10.236>= 5.11, < 5.15.180>= 5.16, < 6.1.132>= 6.2, < 6.6.84>= 6.7, < 6.12.20>= 6.13, < 6.13.8= 6.14

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.4.292 / 5.10.236 / 5.15.180 or later
Fixed in 5.4.2925.10.2365.15.180
Vendor patch git.kernel.org →
Recommended fix High confidence

Upgrade to kernel >=5.4.292, >=5.10.236, >=5.15.180, or >=6.1.132 (whichever corresponds to the current branch, preferring the latest stable release)

  1. 1. Identify the current running kernel version using `uname -r`
  2. 2. Determine the appropriate target version based on the current kernel branch: for 4.15-5.4.x upgrade to >=5.4.292; for 5.5-5.10.x upgrade to >=5.10.236; for 5.11-5.15.x upgrade to >=5.15.180; for 5.16-6.1.x upgrade to >=6.1.132
  3. 3. Update the kernel package using the distribution's package manager (e.g., `apt-get update && apt-get install linux-image-<version>` for Debian/Ubuntu, or `yum update kernel` for RHEL/CentOS)
  4. 4. Reboot the system to load the new kernel: `sudo reboot`
  5. 5. Verify the fix is applied by checking the kernel version (`uname -r`) and confirming the drm/amd/display driver no longer produces the warning in dmesg
Caveat Kernel upgrades carry standard risk of regression; ensure backup and test in staging if possible. This is a low-risk display driver bug fix.

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-21956 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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