Security readout for executives and security teams
Plain-English summary
CVE-2025-21940 is a Linux kernel bug in AMD KFD queue handling. A local low-privileged user may be able to trigger a NULL pointer dereference and crash affected systems, creating a denial-of-service risk. The sources do not show data theft, privilege escalation, or confirmed active exploitation.
Executive priority
Handle in normal patch cycles for most environments, faster for shared Linux GPU compute systems. The business risk is service disruption, not known compromise, based on the supplied evidence.
Technical view
The flaw is CWE-476 in drm/amdkfd, specifically kfd_queue_acquire_buffers, found through KFD IOCTL fuzzing. The CVSS 3.1 vector is local, low complexity, low privileges, no user interaction, unchanged scope, and high availability impact only. Kernel stable commit references are provided as the resolution evidence.
Likely exposure
Exposure is most relevant to Linux systems running affected kernel builds with AMD KFD/AMDGPU compute functionality available to local users. The supplied version data is incomplete for distro packages, so confirm exposure through vendor kernel advisories and backport status.
Exploitation context
The bundle marks KEV as false and provides no source claiming active exploitation. The described trigger came from IOCTL fuzzing, and the CVSS vector requires local access with low privileges. Treat this primarily as local denial-of-service exposure unless vendor guidance adds new evidence.
Researcher notes
Do not assume remote reachability or privilege escalation from the bundle. Validation should focus on local KFD device exposure, AMD GPU workloads, exact kernel build lineage, and whether the referenced stable commits are present in deployed packages.
Mitigation direction
- Update to a vendor kernel containing the referenced stable fixes.
- Check distribution advisories for backported fixes to older kernel package versions.
- Prioritize GPU compute hosts shared by untrusted or semi-trusted users.
- Where feasible, reduce untrusted local access to affected GPU/KFD devices until patched.
Validation and detection
- Inventory Linux kernel versions on AMD GPU compute systems.
- Check whether vendor packages include the cited stable kernel fixes.
- Review access controls for local users with GPU/KFD device access.
- Confirm vulnerability scanners map distro backports correctly, not only upstream versions.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-476: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2025-21940 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.
SSVC decision data
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/c3cbeafb4e0001d9146df50b470885e02664f3c7CVE reference, Linux
- https://git.kernel.org/stable/c/33eb8041c5d6c19d46e7bfd23a031844336afd80CVE reference, Linux
- https://git.kernel.org/stable/c/fd617ea3b79d2116d53f76cdb5a3601c0ba6e42fCVE reference, Linux
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
NULL Pointer Dereference
NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.