CVE-2026-23220
ksmbd: fix infinite loop caused by next_smb2_rcv_hdr_off reset in error paths
Description
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.
INFO
Published Date :
Feb. 18, 2026, 4:22 p.m.
Last Modified :
March 18, 2026, 2:52 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the Linux kernel to the patched version.
- Verify the ksmbd module is running correctly.
- Monitor system performance after the update.
- Check kernel logs for "bad smb2 signature" messages.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-23220.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-23220 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-23220
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-23220 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-23220 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
Mar. 18, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-835 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:6.6:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.6:-:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.15.145 up to (excluding) 5.16 *cpe:2.3:o:linux:linux_kernel:6.6:rc7:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 6.19.1 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.72 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.11 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.1.71 up to (excluding) 6.1.164 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.6.1 up to (excluding) 6.6.125 Added Reference Type kernel.org: https://git.kernel.org/stable/c/010eb01ce23b34b50531448b0da391c7f05a72af Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/5accdc5b7f28a81bbc5880ac0b8886e60c86e8c8 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/71b5e7c528315ca360a1825a4ad2f8ae48c5dc16 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/9135e791ec2709bcf0cda0335535c74762489498 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/f7b1c2f5642bbd60b1beef1f3298cbac81eb232c Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/fb3b66bd72deb5543addaefa67963b34fb163a7b Types: Patch -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Feb. 23, 2026
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/010eb01ce23b34b50531448b0da391c7f05a72af -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Feb. 19, 2026
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/fb3b66bd72deb5543addaefa67963b34fb163a7b -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Feb. 18, 2026
Action Type Old Value New Value Added Description 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. Added Reference https://git.kernel.org/stable/c/5accdc5b7f28a81bbc5880ac0b8886e60c86e8c8 Added Reference https://git.kernel.org/stable/c/71b5e7c528315ca360a1825a4ad2f8ae48c5dc16 Added Reference https://git.kernel.org/stable/c/9135e791ec2709bcf0cda0335535c74762489498 Added Reference https://git.kernel.org/stable/c/f7b1c2f5642bbd60b1beef1f3298cbac81eb232c