CVE-2026-31608Network attack vector

Kernel memory corruption via KSMBD send-message double free

Published Apr 24, 2026 · Updated Apr 24, 2026

Double free in the Linux Kernel KSMBD SMB Direct send path allows remote attackers to corrupt kernel memory via an RDMA connection. When post_sendmsg moves a send message to the batch list, smb_direct_flush_send_list() frees it, and the caller then frees the same object again. Exposure requires KSMBD with SMB Direct and RDMA enabled; successful exploitation can crash the kernel or execute code in kernel context.

CVSS severity9.8
Critical
EPSS probability0.46%
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

Double free in the Linux Kernel KSMBD SMB Direct send path allows remote attackers to corrupt kernel memory via an RDMA connection. When post_sendmsg moves a send message to the batch list, smb_direct_flush_send_list() frees it, and the caller then frees the same object again. Exposure requires KSMBD with SMB Direct and RDMA enabled; successful exploitation can crash the kernel or execute code in kernel context.

The record

CVE
CVE-2026-31608
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-415, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 2026Record 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2ba03f46132b0d1a7bafb86e1ef61951a2254023
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6968c91fab05b8fc4d6700e0cf34472bb422df25
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <830de6eeb9db4cb7e758201fb99328ef4ca4b032

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2ba03f46132b0d1a7bafb86e1ef61951a2254023; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6968c91fab05b8fc4d6700e0cf34472bb422df25; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <830de6eeb9db4cb7e758201fb99328ef4ca4b032

Published CVSS scores

9.8kernel.orgCVSS: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.

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-415Double Free
T1190Exploit Public-Facing Application

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