CVE-2026-23220
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Linux kernel Affected 2 releases
| Version | Status | Fixed in |
|---|---|---|
| 6.6 | Affected | — |
| — | Affected | 5.16 |
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 6.12.73-1 |
| sid | Fixed | 6.18.12-1 |
| forky | Fixed | 6.18.12-1 |
| bullseye | Fixed | 0 |
| bookworm | Fixed | 6.1.164-1 |
References
- https://www.suse.com/security/cve/CVE-2026-23220.html
- https://security-tracker.debian.org/tracker/CVE-2026-23220
- https://git.kernel.org/stable/c/010eb01ce23b34b50531448b0da391c7f05a72af
- https://git.kernel.org/stable/c/544adb0a6658ea1bff4064723761dbf05f95b1e2
- https://git.kernel.org/stable/c/5accdc5b7f28a81bbc5880ac0b8886e60c86e8c8
- https://git.kernel.org/stable/c/71b5e7c528315ca360a1825a4ad2f8ae48c5dc16
- https://git.kernel.org/stable/c/9135e791ec2709bcf0cda0335535c74762489498
- https://git.kernel.org/stable/c/f7b1c2f5642bbd60b1beef1f3298cbac81eb232c
- https://git.kernel.org/stable/c/fb3b66bd72deb5543addaefa67963b34fb163a7b
- https://cert-portal.siemens.com/productcert/html/ssa-253495.html
CWEs
CWE-835
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.