CVE-2026-43490Network attack vector

Kernel memory corruption via unchecked inherited SID length

Published May 15, 2026 · Updated May 15, 2026

Out-of-bounds access in Linux Kernel ksmbd allows remote authenticated users to read or corrupt kernel memory through SMB requests. smb_inherit_dacl() trusts sid.num_subauth from an inheritable ACE without confirming that the variable-length SID fits the ACE, while smb_set_ace() uses that unchecked count for buffer sizing. Exploitation requires a valid SMB session with write and create access to an ACL-xattr-enabled share; consequences include heap disclosure, corruption, and kernel panic.

CVSS severity8.8
High
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in Linux Kernel ksmbd allows remote authenticated users to read or corrupt kernel memory through SMB requests. smb_inherit_dacl() trusts sid.num_subauth from an inheritable ACE without confirming that the variable-length SID fits the ACE, while smb_set_ace() uses that unchecked count for buffer sizing. Exploitation requires a valid SMB session with write and create access to an ACL-xattr-enabled share; consequences include heap disclosure, corruption, and kernel panic.

The record

CVE
CVE-2026-43490
Published
May 15, 2026
Updated
May 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-787, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 15, 2026CVE publishedPublication date reported by the CVE source.
  2. May 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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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 <1aa60fea7f637c071f529ad6784aecca2f2f0c5f
  3. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <47c6e37a77b10e74f70d845ba4ea5d3cafa00336
  4. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <996454bc0da84d5a1dedb1a7861823087e01a7ae
  5. Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <c1d95c995d5bcb24b639200a899eda59cb1e6d64

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.15; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <1aa60fea7f637c071f529ad6784aecca2f2f0c5f; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <47c6e37a77b10e74f70d845ba4ea5d3cafa00336; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <996454bc0da84d5a1dedb1a7861823087e01a7ae; version=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <c1d95c995d5bcb24b639200a899eda59cb1e6d64

Published CVSS scores

8.8Linux kernel CNACVSS: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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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