CVE-2025-39692

Service crash via premature RDMA workqueue destruction

Published Sep 5, 2025 · Updated Sep 5, 2025

NULL-pointer dereference in affected Linux kernel versions allows local users to crash a ksmbd server during SMB Direct shutdown. ksmbd_rdma_destroy destroys the smb_direct_wq workqueue before stop_sessions terminates existing connections, leaving them to queue work through a NULL pointer. Exploitation requires local low-privileged access and an enabled ksmbd SMB Direct configuration; the resulting availability impact is a kernel crash.

CVSS severity5.5
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

NULL-pointer dereference in affected Linux kernel versions allows local users to crash a ksmbd server during SMB Direct shutdown. ksmbd_rdma_destroy destroys the smb_direct_wq workqueue before stop_sessions terminates existing connections, leaving them to queue work through a NULL pointer. Exploitation requires local low-privileged access and an enabled ksmbd SMB Direct configuration; the resulting availability impact is a kernel crash.

The record

CVE
CVE-2025-39692
Published
Sep 5, 2025
Updated
Sep 5, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 5, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <003e6a3150299f681f34cb189aa068018cef6a45
  2. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <212eb86f75b4d7b82f3d94aed95ba61103bccb93
  3. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <524e90e58a267dad11e23351d9e4b1f941490976
  4. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <bac7b996d42e458a94578f4227795a0d4deef6fa
  5. Affected versionversion=0626e6641f6b467447c81dd7678a69c66f7746cf <e41e33400516702427603f8fbbec43c91ede09c0
  6. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0626e6641f6b467447c81dd7678a69c66f7746cf <003e6a3150299f681f34cb189aa068018cef6a45; version=0626e6641f6b467447c81dd7678a69c66f7746cf <212eb86f75b4d7b82f3d94aed95ba61103bccb93; version=0626e6641f6b467447c81dd7678a69c66f7746cf <524e90e58a267dad11e23351d9e4b1f941490976; version=0626e6641f6b467447c81dd7678a69c66f7746cf <bac7b996d42e458a94578f4227795a0d4deef6fa; version=0626e6641f6b467447c81dd7678a69c66f7746cf <e41e33400516702427603f8fbbec43c91ede09c0; version=5.15

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo