CVE-2026-31706Network attack vector

Authenticated kernel memory corruption via malformed inherited DACL

Published May 1, 2026 · Updated May 1, 2026

Memory corruption in Linux Kernel ksmbd allows remote authenticated users to crash the server via a malformed parent DACL. smb_inherit_dacl() trusts the DACL xattr's num_aces when sizing a heap allocation and accepts undersized ACEs while walking partially initialized memory. The path requires an ACL-enabled ksmbd share plus write or ACL-setting access to a tampered parent security.NTACL; it can expose kernel data, corrupt ACL state, and destabilize or crash the server.

CVSS severity8.8
High
EPSS probability0.37%
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

Memory corruption in Linux Kernel ksmbd allows remote authenticated users to crash the server via a malformed parent DACL. smb_inherit_dacl() trusts the DACL xattr's num_aces when sizing a heap allocation and accepts undersized ACEs while walking partially initialized memory. The path requires an ACL-enabled ksmbd share plus write or ACL-setting access to a tampered parent security.NTACL; it can expose kernel data, corrupt ACL state, and destabilize or crash the server.

The record

CVE
CVE-2026-31706
Published
May 1, 2026
Updated
May 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 1, 2026CVE publishedPublication date reported by the CVE source.
  2. May 1, 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=5.15
  2. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <063a7409b0de46d7c770b65bb0338e6fdb3b1f0a
  3. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <3e4e2ea2a781018ed5d75f969e3e5606beb66e48
  4. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <3e5360b422dd741cb315654a191fa73869a37414
  5. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <59c32abaaec9cdd6164811c7e864e72f7554b82d

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.15; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <063a7409b0de46d7c770b65bb0338e6fdb3b1f0a; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <3e4e2ea2a781018ed5d75f969e3e5606beb66e48; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <3e5360b422dd741cb315654a191fa73869a37414; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <59c32abaaec9cdd6164811c7e864e72f7554b82d

Published CVSS scores

8.8kernel.orgCVSS:3.1/AV:N/AC:L/PR:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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