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CVE Record

CVE-2025-40021: tracing: dynevent: Add a missing lockdown check on dynevent

In the Linux kernel, the following vulnerability has been resolved: tracing: dynevent: Add a missing lockdown check on dynevent Since dynamic_events interface on tracefs is compatible with kprobe_events and uprobe_events, it should also check the lockdown status and reject if it is set.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue is a missing lockdown enforcement check in the tracefs dynamic_events interface. On systems relying on kernel lockdown, dynamic_events should have been blocked like kprobe_events and uprobe_events. The sources do not provide a CVSS score, confirmed exploitation, or detailed business impact.

Executive priority

Treat as a patch-management and hardening issue for Linux hosts using kernel lockdown. Prioritize security-sensitive systems first, but avoid emergency escalation unless vendor guidance or new evidence shows practical exploitation.

Technical view

The flaw is in Linux kernel tracing dynevent handling. Because dynamic_events is compatible with kprobe_events and uprobe_events, it should call the same lockdown status check and reject writes when lockdown is active. Kernel stable commits add that missing check.

Likely exposure

Exposure appears limited to Linux systems running affected kernel versions where tracefs dynamic_events is present and kernel lockdown is expected to constrain tracing interfaces. The source bundle does not define remote exposure, required privileges, or distribution-specific affected package versions.

Exploitation context

The CVE is not listed as KEV in the provided bundle, and no cited source states active exploitation. The bundle describes a protection bypass condition, but does not provide exploitability details, prerequisites, or observed attacks.

Researcher notes

Key missing evidence: CVSS, CWE, privilege requirements, impact boundaries, and distro package mappings. The strongest technical signal is the kernel fix aligning dynamic_events with existing kprobe_events and uprobe_events lockdown enforcement.

Mitigation direction

  • Apply kernel or distribution updates containing the referenced stable fixes.
  • Check Linux distribution advisories for exact affected and fixed package versions.
  • Prioritize systems that depend on kernel lockdown for security boundaries.
  • Restrict tracefs access according to vendor hardening guidance.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and containers hosts.
  • Map installed kernels to distribution advisories or referenced stable commits.
  • Confirm lockdown-enabled test systems reject dynamic_events changes as expected.
  • Review whether tracefs is mounted and who can access it.
Prepared
Confidence
medium
Sources
9

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.

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CVE-2025-40021 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

0CVSS vectors
3Timeline events
0ADP providers
8Source links

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
LinuxLinux17911ff38aa58d3c95c07589dbf5d3564c4cf3c5, 17911ff38aa58d3c95c07589dbf5d3564c4cf3c5, 17911ff38aa58d3c95c07589dbf5d3564c4cf3c5, 17911ff38aa58d3c95c07589dbf5d3564c4cf3c5, 17911ff38aa58d3c95c07589dbf5d3564c4cf3c5, 17911ff38aa58d3c95c07589dbf5d3564c4cf3c5, 17911ff38aa58d3c95c07589dbf5d3564c4cf3c5unaffected
LinuxLinux5.4, 0, 5.10.245, 5.15.194, 6.1.155, 6.6.109, 6.12.50, 6.16.10, 6.17affected
Weakness

CWE details

No CWE listed

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