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CVE Record

CVE-2025-38717: net: kcm: Fix race condition in kcm_unattach()

In the Linux kernel, the following vulnerability has been resolved: net: kcm: Fix race condition in kcm_unattach() syzbot found a race condition when kcm_unattach(psock) and kcm_release(kcm) are executed at the same time. kcm_unattach() is missing a check of the flag kcm->tx_stopped before calling queue_work(). If the kcm has a reserved psock, kcm_unattach() might get executed between cancel_work_sync() and unreserve_psock() in kcm_release(), requeuing kcm->tx_work right before kcm gets freed in kcm_done(). Remove kcm->tx_stopped and replace it by the less error-prone disable_work_sync().

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux kernel race in the KCM networking subsystem can cause work to run after related memory is freed. A local, low-privileged attacker may be able to crash the system or potentially compromise confidentiality and integrity. The source bundle rates it CVSS 7.8; practical exploitability is not established.

Executive priority

Treat as a high-priority kernel maintenance issue, especially on shared systems or infrastructure running untrusted workloads. It is not described as remotely exploitable, and active exploitation is unsupported. Schedule prompt patching through normal emergency or accelerated maintenance processes based on local-user exposure.

Technical view

Concurrent kcm_unattach() and kcm_release() operations can requeue tx_work after cancel_work_sync() but before the KCM object is freed, creating a use-after-free condition. The upstream correction replaces the tx_stopped flag mechanism with disable_work_sync(), preventing work from being requeued during teardown.

Likely exposure

Exposure is limited to affected Linux kernels where the KCM networking subsystem is present and reachable by a local low-privileged user. The supplied version data spans Linux 4.6 through listed later releases, but does not clearly map fixed commits to every distribution kernel or stable branch.

Exploitation context

The CVSS vector indicates local access, low complexity, low privileges, and no user interaction. KEV is false, and the supplied sources provide no evidence of active exploitation or a public working exploit. Discovery by syzbot demonstrates the race condition, not malicious exploitation.

Researcher notes

The core failure is teardown synchronization: kcm_unattach() could requeue tx_work between cancellation and unreservation in kcm_release(), immediately before kcm_done() freed the object. The linked stable commits are authoritative remediation references, but the bundle lacks precise per-branch and distribution package mappings.

Mitigation direction

  • Install a vendor-supported kernel containing the applicable stable fix or backport.
  • Confirm the distribution's advisory maps CVE-2025-38717 to the installed kernel build.
  • Prioritize shared, multi-user, and untrusted-workload systems where local users increase exposure.
  • If no corrected package is available, obtain interim risk-reduction guidance from the kernel vendor.

Validation and detection

  • Inventory installed kernel releases across physical hosts, virtual machines, and container hosts.
  • Check vendor changelogs or source trees for the applicable linked fix or documented backport.
  • Verify systems boot into the corrected kernel after maintenance.
  • Rescan affected assets and record vendor-specific fixed-version evidence.
Prepared
Confidence
medium
Sources
6

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-2025-38717 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
5Source 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-2025-38717Attack 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
LinuxLinuxab7ac4eb9832e32a09f4e8042705484d2fb0aad3, ab7ac4eb9832e32a09f4e8042705484d2fb0aad3, ab7ac4eb9832e32a09f4e8042705484d2fb0aad3, ab7ac4eb9832e32a09f4e8042705484d2fb0aad3unaffected
LinuxLinux4.6, 0, 6.12.43, 6.15.11, 6.16.2, 6.17affected
Weakness

CWE details

No CWE listed

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