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CVE Record

CVE-2026-31766: drm/amdgpu: validate doorbell_offset in user queue creation

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: validate doorbell_offset in user queue creation amdgpu_userq_get_doorbell_index() passes the user-provided doorbell_offset to amdgpu_doorbell_index_on_bar() without bounds checking. An arbitrarily large doorbell_offset can cause the calculated doorbell index to fall outside the allocated doorbell BO, potentially corrupting kernel doorbell space. Validate that doorbell_offset falls within the doorbell BO before computing the BAR index, using u64 arithmetic to prevent overflow. (cherry picked from commit de1ef4ffd70e1d15f0bf584fd22b1f28cbd5e2ec)

HighCVSS 7.1Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A local, low-privileged user may supply an oversized AMD GPU queue offset that reaches beyond allocated kernel memory. The resulting corruption could alter system state or crash the host. The supplied CVSS score is 7.1, with high integrity and availability impact but no stated confidentiality impact.

Executive priority

Treat as high priority on multi-user GPU compute, workstation, or shared development systems because low-privileged local users may disrupt or corrupt the host. Internet-only systems without local user access are less directly exposed. Use vendor package guidance to resolve the ambiguous upstream version information.

Technical view

The amdgpu user-queue path passed a user-controlled doorbell_offset into BAR index calculation without first checking it against the doorbell buffer object. An excessive value could produce an out-of-range index and corrupt kernel doorbell space. The fix validates the offset before calculation and uses 64-bit arithmetic to prevent overflow.

Likely exposure

Exposure requires Linux systems using the AMDGPU driver on an affected kernel and a local account able to reach user-queue creation. The bundle lists versions including 6.16, 6.18.22, 6.19.12, and 7.0, but its version data is ambiguous; confirm applicability through the kernel or distribution vendor.

Exploitation context

The CVSS vector indicates local access, low complexity, low privileges, and no user interaction. CISA KEV status is false, and the supplied sources provide no evidence of active exploitation. Potential impact is kernel-space corruption affecting integrity or availability rather than disclosed data theft.

Researcher notes

Review the user-queue doorbell allocation boundary and confirm validation occurs before BAR index calculation using overflow-safe 64-bit arithmetic. The supplied record contains unclear affected-version entries, including “0” and repeated commit identifiers, so avoid inferring a continuous vulnerable range without vendor confirmation.

Mitigation direction

  • Install a vendor-supported kernel containing the cited AMDGPU offset-validation fix.
  • Check Linux distribution advisories for exact fixed packages and backport status.
  • Prioritize shared GPU hosts where untrusted local users can access AMDGPU user queues.
  • Until patched, reduce untrusted local access to affected AMD GPU systems where operationally feasible.

Validation and detection

  • Inventory Linux hosts with AMD GPUs and the amdgpu driver loaded.
  • Record running kernel versions and compare them with distribution security advisories.
  • Confirm installed kernel source or package changelog includes the cited stable fix.
  • After updating, verify the fixed kernel is running following any required reboot.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2026-31766 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.1 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
0ADP providers
4Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.1CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H1.85.2Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.1High
CVSS 3.1 vector shape for CVE-2026-31766Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxf09c1e6077abd1bc2ddd2b97e1135215801ca7f9, f09c1e6077abd1bc2ddd2b97e1135215801ca7f9, f09c1e6077abd1bc2ddd2b97e1135215801ca7f9unaffected
LinuxLinux6.16, 0, 6.18.22, 6.19.12, 7.0affected
Weakness

CWE details

No CWE listed

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