ksmbd: fix infinite loop caused by next_smb2_rcv_hdr_off reset in error paths
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-835.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.15.145 to before 5.15.203; 6.1.71 to before 6.1.164 | 5.15.203, 6.1.164 | Patch available | CNA |
| Linux | Linux | 6.6 and later | 5.15.203, 6.1.164, 6.6.125, 6.12.72, 6.18.11, 6.19.1, 7.0 | Patch available | CNA |
- Linux VendorLinux Affected 5.15.145 to before 5.15.203; 6.1.71 to before 6.1.164 Fixed in 5.15.203, 6.1.164 Patch available CNA
- Linux VendorLinux Affected 6.6 and later Fixed in 5.15.203, 6.1.164, 6.6.125, 6.12.72, 6.18.11, 6.19.1, 7.0 Patch available CNA
CPE configurations NVD · 4
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 5.15.145 to before 5.16; 6.1.71 to before 6.1.164; 6.6.1 to before 6.6.125; 6.7 to before 6.12.72; 6.13 to before 6.18.11; 6.19 to before 6.19.1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.6:-:*:*:*:*:*:* | 6.6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.6:rc6:*:*:*:*:*:* | 6.6 rc6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.6:rc7:*:*:*:*:*:* | 6.6 rc7 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.15.145 to before 5.16; 6.1.71 to before 6.1.164; 6.6.1 to before 6.6.125; 6.7 to before 6.12.72; 6.13 to before 6.18.11; 6.19 to before 6.19.1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.6:-:*:*:*:*:*:* Versions 6.6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.6:rc6:*:*:*:*:*:* Versions 6.6 rc6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.6:rc7:*:*:*:*:*:* Versions 6.6 rc7 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.15.203, 6.1.164
- Fix · CNA Linux (Linux) Fixed in 5.15.203, 6.1.164, 6.6.125, 6.12.72, 6.18.11, 6.19.1, 7.0
Vendor assessments
Red Hat
Not affected: 5 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-23220
- 2026-10-03 Alias added: GHSA-9wwr-2jh3-482p
References
Patch 6
- https://git.kernel.org/stable/c/fb3b66bd72deb5543addaefa67963b34fb163a7b
- https://git.kernel.org/stable/c/5accdc5b7f28a81bbc5880ac0b8886e60c86e8c8
- https://git.kernel.org/stable/c/f7b1c2f5642bbd60b1beef1f3298cbac81eb232c
- https://git.kernel.org/stable/c/71b5e7c528315ca360a1825a4ad2f8ae48c5dc16
- https://git.kernel.org/stable/c/9135e791ec2709bcf0cda0335535c74762489498
- https://git.kernel.org/stable/c/010eb01ce23b34b50531448b0da391c7f05a72af
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- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2026-23220 · CVE Program
- CVE-2026-23220 · NVD
- FIRST EPSS
- GHSA-9wwr-2jh3-482p · GitHub Advisory Database · CC BY 4.0
- CVE-2026-23220 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences