PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-46204 Linux CVE debrief

A vulnerability in the Linux kernel's AMDGPU driver for VCN4 (Video Core Next 4) hardware could allow out-of-bounds (OOB) memory reads during command buffer parsing. The issue stems from insufficient bounds checking when parsing Indirect Buffers (IBs) in the VCN4 video decode/encode engine driver. The fix rewrites the IB parsing logic to use `amdgpu_ib_get_value()`, a helper function that performs proper bounds validation before accessing buffer data. This vulnerability affects systems with AMD GPUs featuring VCN4 hardware acceleration for video processing. Successful exploitation could lead to information disclosure from kernel memory or potentially cause system instability. The vulnerability was resolved by replacing direct buffer access with the bounds-checked helper function across affected code paths.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-28
Original CVE updated
2026-06-10
Advisory published
2026-05-28
Advisory updated
2026-06-10

Who should care

Organizations running Linux workstations or servers with AMD Radeon GPUs utilizing VCN4 video acceleration; cloud providers offering GPU instances with AMD hardware; media processing pipelines dependent on AMD hardware video encode/decode; security teams monitoring kernel driver vulnerabilities affecting graphics subsystems

Technical summary

The vulnerability exists in the Direct Rendering Manager (DRM) AMDGPU driver's VCN4 (Video Core Next 4) component, specifically in the Indirect Buffer (IB) parsing code. VCN4 is AMD's hardware video decode/encode engine found in modern Radeon GPUs. The original code performed direct memory access on IB data without verifying buffer bounds, enabling out-of-bounds reads when processing malformed or truncated command buffers. The resolution replaces unsafe direct access with `amdgpu_ib_get_value()`, a kernel helper that validates offsets against buffer limits before dereferencing. The five referenced stable commits indicate backports to multiple supported kernel branches, suggesting the fix applies across several kernel versions. This is a local vulnerability requiring ability to submit GPU command buffers, typically through DRM device access.

Defensive priority

medium

Recommended defensive actions

  • Apply kernel updates containing the referenced stable commits when available through distribution channels
  • Prioritize patching systems with AMD GPUs utilizing VCN4 video acceleration for decode/encode workloads
  • Monitor vendor security advisories for kernel package updates addressing this vulnerability
  • Review system logs for unusual AMDGPU driver errors that may indicate exploitation attempts
  • Consider disabling VCN4 hardware acceleration if patching is delayed and video acceleration is not business-critical

Evidence notes

CVE description confirms OOB read vulnerability in drm/amdgpu/vcn4 IB parsing. Fix involves using amdgpu_ib_get_value() for bounds checking. Multiple stable kernel commits provided indicate backports to supported branches.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-46204 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-46204

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-46204 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-46204

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/1dc005775fb5b3f86464406452b17364f85581d3

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/2444eb0ec8283f4a3845eb7febad378476e1ba3c

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/5c3e8ebad0c9e2354ddfa8f2148dc4f70a3b4bd1

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/a6d5563ba1f03a049561cd347574613167294e8d

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/d0802a8877d730260d4af4dd4e0b6cde7e0e593f

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.