CVE-2026-23220

Medium

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix infinite loop caused by next_smb2_rcv_hdr_off reset in error paths The problem occurs when a signed request fails smb2 signature verification check. In __process_request(), if check_sign_req() returns an error, set_smb2_rsp_status(work, STATUS_ACCESS_DENIED) is called. set_smb2_rsp_status() set work->next_smb2_rcv_hdr_off as zero. By resetting next_smb2_rcv_hdr_off to zero, the pointer to the next command in the chain is lost. Consequently, is_chained_smb2_message() continues to point to the same request header instead of advancing. If the header's NextCommand field is non-zero, the function returns true, causing __handle_ksmbd_work() to repeatedly process the same failed request in an infinite loop. This results in the kernel log being flooded with "bad smb2 signature" messages and high CPU usage. This patch fixes the issue by changing the return value from SERVER_HANDLER_CONTINUE to SERVER_HANDLER_ABORT. This ensures that the processing loop terminates immediately rather than attempting to continue from an invalidated offset.

Package Linux Kernel
Published 2026-02-18
Last modified 2026-06-02
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

5.5

out of 10
Medium
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness type

CWE-835

CVE-2026-23220 is a Infinite Loop vulnerability

What is Infinite Loop?

The product contains an iteration that does not exit even when it should. Learn more on MITRE CWE

Affected versions

Linux kernel versions 5.15.145, 6.1.71, 6.6 and later are affected. Fixed in 5.15.203, 6.1.164, 6.6.125, 6.12.72, 6.18.11, 6.19.1, 7.0 and their respective stable series.

Affected from
≥ 5.15.145 ≥ 6.1.71 ≥ 6.6
Fixed in
✓ 5.15.203 5.15.x ✓ 6.1.164 6.1.x ✓ 6.6.125 6.6.x ✓ 6.12.72 6.12.x ✓ 6.18.11 6.18.x ✓ 6.19.1 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-23220 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

7 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2026-23220?

    CVE-2026-23220 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as an Infinite Loop flaw (CWE-835) . It affects Linux kernel versions from 5.15.145 onward and has been patched in 5.15.203, 6.1.164, 6.6.125 and others. CVE-2026-23220 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-23220?

    CVE-2026-23220 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2026-23220?

    Yes — CVE-2026-23220 has been patched. Fixed versions include 5.15.203, 6.1.164, 6.6.125 and others. If you are running Linux kernel 5.15.145 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-23220 actively exploited?

    No — CVE-2026-23220 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is Infinite Loop (CWE-835)?

    The product contains an iteration that does not exit even when it should. View CWE-835 on MITRE CWE →

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