CVE-2026-23220

ksmbd: fix infinite loop caused by next_smb2_rcv_hdr_off reset in error paths

MEDIUM
5.5
CVSS Score
Published: February 18, 2026 at 02:53 PM UTC
Updated: June 17, 2026 at 10:21 AM UTC
2 products affected across 2 vendorsLinux KernelRUGGEDCOM RST2428P Firmware

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.1%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.15.145 ≤ v < 5.15.2035.15.145 ≤ v < 5.166.1.71 ≤ v < 6.1.1646.13 ≤ v < 6.18.116.19 ≤ v < 6.19.16.6 ≤ v < 6.12.726.6 ≤ v < 6.18.116.6 ≤ v < 6.19.16.6 ≤ v < 6.6.1256.6 ≤ v < 7.06.6.1 ≤ v < 6.6.1256.7 ≤ v < 6.12.724b9b7ea1ffb1e34f01fa5726d0c184931b9ba5655.15.1456.1.716.66.6 rc66.6 rc7943cebf9ea3415ddefcd670d24d8883e97ba3d60be0f89d4419dc5413a1cf06db3671c9949be0d52
Vendor states this is fixed in 010eb01ce23b34b50531448b0da391c7f05a72af (fixed)
Vendor states this is fixed in 544adb0a6658ea1bff4064723761dbf05f95b1e2 (fixed)
Vendor states this is fixed in 5accdc5b7f28a81bbc5880ac0b8886e60c86e8c8 (fixed)
Vendor states this is fixed in 71b5e7c528315ca360a1825a4ad2f8ae48c5dc16 (fixed)
Vendor states this is fixed in 9135e791ec2709bcf0cda0335535c74762489498 (fixed)
Vendor states this is fixed in f7b1c2f5642bbd60b1beef1f3298cbac81eb232c (fixed)
Vendor states this is fixed in fb3b66bd72deb5543addaefa67963b34fb163a7b (fixed)
Vendor states this is fixed in 5.15.203 (unaffected)
Affected range stops below 5.16, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 6.1.164 (unaffected)
Vendor states this is fixed in 6.12.72 (unaffected)
Vendor states this is fixed in 6.18.11 (unaffected)
Vendor states this is fixed in 6.19.1 (unaffected)
Vendor states this is fixed in 6.6 (unaffected)
Vendor states this is fixed in 6.6.125 (unaffected)
Vendor states this is fixed in 7.0 (unaffected)
v < V4.0
Affected range stops below V4.0, so it looks safe — our inference, not a vendor statement

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-835

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