CVE-2026-8449Public exploitNetwork attack vector

Kernel memory corruption via unchecked inherited SID length

Published May 12, 2026 · Updated May 12, 2026

Memory corruption in Linux ksmbd allows remote authenticated users to corrupt kernel memory through crafted inherited ACLs. smb_inherit_dacl() trusts sid.num_subauth without confirming that the variable-length SID fits its ACE, allowing compare_sids() to read past the ACE and smb_set_ace() to advance inherited-buffer accounting beyond its allocation. Directory-creation permission and an inheritable malicious DACL are required; bounded outcomes include kernel memory disclosure, corruption, or a kernel crash, and CVE-2026-8449 is rejected in favor of CVE-2026-43490.

CVSS severity8.8
High
EPSS probabilityUnavailable
No score available in this record
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 ksmbd allows remote authenticated users to corrupt kernel memory through crafted inherited ACLs. smb_inherit_dacl() trusts sid.num_subauth without confirming that the variable-length SID fits its ACE, allowing compare_sids() to read past the ACE and smb_set_ace() to advance inherited-buffer accounting beyond its allocation. Directory-creation permission and an inheritable malicious DACL are required; bounded outcomes include kernel memory disclosure, corruption, or a kernel crash, and CVE-2026-8449 is rejected in favor of CVE-2026-43490.

The record

CVE
CVE-2026-8449
Published
May 12, 2026
Updated
May 12, 2026
Vendor
The Linux Kernel Organization
Product
ksmbd
Classifications
CWE-787, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 12, 2026CVE publishedPublication date reported by the CVE source.
  2. May 12, 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=0 <=996454b

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · ksmbdversion=0 <=996454b

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 exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

Public exploit references

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