CVE-2026-23220

Denial of service via invalidated SMB2 chain offset

Published Feb 18, 2026 · Updated Feb 18, 2026

Infinite-loop denial of service in Linux Kernel ksmbd allows local users to consume CPU and flood logs via a crafted SMB2 request. A failed signature check clears next_smb2_rcv_hdr_off, but processing continues, so the compound-request loop repeatedly handles the same header. Reachability requires active ksmbd and a signed compound request with a nonzero NextCommand field; impact is bounded to CPU consumption and kernel-log flooding.

CVSS severity5.5
Medium
EPSS probability0.12%
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

Infinite-loop denial of service in Linux Kernel ksmbd allows local users to consume CPU and flood logs via a crafted SMB2 request. A failed signature check clears next_smb2_rcv_hdr_off, but processing continues, so the compound-request loop repeatedly handles the same header. Reachability requires active ksmbd and a signed compound request with a nonzero NextCommand field; impact is bounded to CPU consumption and kernel-log flooding.

The record

CVE
CVE-2026-23220
Published
Feb 18, 2026
Updated
Feb 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-835, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 18, 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 <5accdc5b7f28a81bbc5880ac0b8886e60c86e8c8
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <71b5e7c528315ca360a1825a4ad2f8ae48c5dc16
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9135e791ec2709bcf0cda0335535c74762489498
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f7b1c2f5642bbd60b1beef1f3298cbac81eb232c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5accdc5b7f28a81bbc5880ac0b8886e60c86e8c8; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <71b5e7c528315ca360a1825a4ad2f8ae48c5dc16; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9135e791ec2709bcf0cda0335535c74762489498; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f7b1c2f5642bbd60b1beef1f3298cbac81eb232c

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
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