CVE-2025-39932Network attack vector

Remote code execution via stale RDMA work

Published Oct 4, 2025 · Updated Oct 4, 2025

Use-after-free in the Linux SMB Direct client allows remote attackers controlling an RDMA server to execute kernel code. During smbd_destroy(), ib_drain_qp() can cause put_receive_buffer() to queue post_send_credits_work after rdma_destroy_qp() frees the queue pair. An already-established SMB Direct mount is required; stale function pointers and queue memory permit kernel-memory access, corruption, or a system crash.

CVSS severity9.8
Critical
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux SMB Direct client allows remote attackers controlling an RDMA server to execute kernel code. During smbd_destroy(), ib_drain_qp() can cause put_receive_buffer() to queue post_send_credits_work after rdma_destroy_qp() frees the queue pair. An already-established SMB Direct mount is required; stale function pointers and queue memory permit kernel-memory access, corruption, or a system crash.

The record

CVE
CVE-2025-39932
Published
Oct 4, 2025
Updated
Oct 4, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 4, 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=4.16
  2. Affected versionversion=f198186aa9bbd60fae7a2061f4feec614d880299 <3fabb1236f2e3ad78d531be0a4ad9f4a4ccdda87
  3. Affected versionversion=f198186aa9bbd60fae7a2061f4feec614d880299 <6ae90a2baf923e85eb037b636aa641250bf4220f
  4. Affected versionversion=f198186aa9bbd60fae7a2061f4feec614d880299 <d9dcbbcf9145b68aa85c40947311a6907277e097

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.16; version=f198186aa9bbd60fae7a2061f4feec614d880299 <3fabb1236f2e3ad78d531be0a4ad9f4a4ccdda87; version=f198186aa9bbd60fae7a2061f4feec614d880299 <6ae90a2baf923e85eb037b636aa641250bf4220f; version=f198186aa9bbd60fae7a2061f4feec614d880299 <d9dcbbcf9145b68aa85c40947311a6907277e097

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
9.8Linux Kernel CVE TeamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

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No observations available

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

Weakness, pattern, technique

T1203Exploitation for Client Execution

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

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Your stack

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