# CVE-2026-89571: linux: In the Linux kernel, the following vulnerability has been resolved:  cxl/features: bound fwctl command payload to the...

CVE-2026-89571 is fixed in linux on 1 platform by DEBIAN-CVE-2026-89571 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-89571
- Priority: High
- CVSS: 7.1 (high)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 11, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  cxl/features: bound fwctl command payload to the input buffer  fwctl_cmd_rpc() copies cmd->in_len bytes into inbuf = kvzalloc(cmd->in_len) and passes inbuf and in_len to ->fw_rpc(). The CXL callback cxlctl_fw_rpc() ignores in_len and never checks the user-controlled op_size against it.  cxlctl_set_feature() bounds op_size only from below (op_size <= sizeof(feat_in->hdr)) and then reads op_size - sizeof(hdr) bytes from feat_in->feat_data via cxl_set_feature(). With a small in_len and a large op_size the first memcpy() already reads past the kvzalloc(in_len) buffer; the out-of-bounds bytes are placed in the mailbox payload and sent to the device, and a large enough op_size can walk into unmapped memory and oops the kernel. The Get paths pin op_size to a fixed size but likewise read the input struct without checking in_len.  Reject, at the single dispatch point, any request whose fixed header plus op_size does not fit in the copied-in buffer. The lower-bound test guards the subtraction and ensures op_size was copied in before it is read.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-89571](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89571.md) | Sep 23, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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