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CVE Record

CVE-2025-21985: drm/amd/display: Fix out-of-bound accesses

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix out-of-bound accesses [WHAT & HOW] hpo_stream_to_link_encoder_mapping has size MAX_HPO_DP2_ENCODERS(=4), but location can have size up to 6. As a result, it is necessary to check location against MAX_HPO_DP2_ENCODERS. Similiarly, disp_cfg_stream_location can be used as an array index which should be 0..5, so the ASSERT's conditions should be less without equal.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A flaw in Linux’s AMD display driver can read or write beyond intended array boundaries. Exploitation requires local, low-privileged access according to the supplied CVSS vector. Successful exploitation could seriously affect confidentiality, integrity, and availability, but the sources do not describe a demonstrated exploit or specific real-world outcome.

Executive priority

Treat this as a high-priority patching issue for affected Linux systems using AMD display functionality, particularly where untrusted users receive local accounts. It is not described as remotely exploitable, actively exploited, or KEV-listed in the supplied evidence, so prioritization should consider local-access exposure and asset importance.

Technical view

The AMD display code can index the four-entry hpo_stream_to_link_encoder_mapping array using larger location values. A related assertion can permit an invalid boundary value for disp_cfg_stream_location, whose valid indices are 0 through 5. The supplied CVSS score is 7.8 with local access, low complexity, low privileges, and no user interaction.

Likely exposure

Exposure is limited to Linux systems containing the affected AMD display code and relevant runtime configuration. The bundle identifies affected kernel version data, including 6.12.20, 6.13.8, and 6.14, but does not clearly define complete version ranges or distribution-specific package status. Confirm exact builds with kernel or distribution guidance.

Exploitation context

The supplied vector indicates local exploitation requiring low privileges; it does not indicate a network attack. The bundle marks KEV false and provides no cited evidence of active exploitation or public weaponization. This does not establish that exploitation is impossible or absent.

Researcher notes

The core defect involves unchecked or incorrectly bounded array indices in drm/amd/display. The mapping has four entries, while location may exceed that boundary; a second index must remain within 0 through 5. The sources do not identify a CWE, reliable trigger, demonstrated impact, exploit chain, or complete commit-to-version mapping.

Mitigation direction

  • Install a vendor kernel update that incorporates the applicable upstream stable fix.
  • Confirm distribution-specific remediation guidance because the supplied version boundaries are incomplete.
  • Reboot affected systems into the updated kernel after installation.
  • Limit untrusted local access until patched; this reduces exposure but does not remove the vulnerable code.

Validation and detection

  • Inventory Linux kernel builds on systems using AMD display functionality.
  • Compare exact kernel packages against distribution advisories and the referenced stable fixes.
  • Verify the running kernel after reboot, not only the installed package version.
  • Confirm applicable fix commits are present when maintaining custom kernels.
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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2025-21985 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2025-21985Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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
LinuxLinux4562236b3bc0a28aeb6ee93b2d8a849a4c4e1c7c, 4562236b3bc0a28aeb6ee93b2d8a849a4c4e1c7c, 4562236b3bc0a28aeb6ee93b2d8a849a4c4e1c7cunaffected
LinuxLinux4.15, 0, 6.12.20, 6.13.8, 6.14affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.