---
id: CVE-2026-80662
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cxl: Fix CXL_HEADERLOG_SIZE to match RAS Capability size

  The CXL r4.0 8.2.4.17.7 RAS Capability Structure has total length 0x58
  bytes (CXL_RAS_CAPABILITY_LENGTH); the …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cxl: Fix CXL_HEADERLOG_SIZE to match RAS Capability size

  The CXL r4.0 8.2.4.17.7 RAS Capability Structure has total length 0x58
  bytes (CXL_RAS_CAPABILITY_LENGTH); the …
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'
published: '2026-08-28'
updated: '2026-08-29'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80662'
references:
  - url: 'https://git.kernel.org/stable/c/6fc1919a6f2ed541484dd1f6cd93374044f8fd3d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c268f949e219f9e179558e836f457f6c5fbec416'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fc5eb0962a5e50d64e711817cc24d67df2d90528'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00164
epssPercentile: 0.0493
ingestedAt: '2026-08-30T03:46:31.469Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

cxl: Fix CXL_HEADERLOG_SIZE to match RAS Capability size

The CXL r4.0 8.2.4.17.7 RAS Capability Structure has total length 0x58
bytes (CXL_RAS_CAPABILITY_LENGTH); the Header Log occupies the trailing
64 bytes at offset 0x18.  CXL_HEADERLOG_SIZE was defined as SZ_512,
eight times the actual on-device size.

header_log_copy() reads CXL_HEADERLOG_SIZE_U32 (128) dwords from the
RAS capability iomap, overrunning the 88-byte mapping by 448 bytes.
The cxl_aer_uncorrectable_error trace event memcpy()s CXL_HEADERLOG_SIZE
(512) bytes from its source.  For the CPER caller the source is
struct cxl_ras_capability_regs::header_log[16] (64 bytes) embedded in a
stack-local cxl_cper_prot_err_work_data, so the memcpy reads 448 bytes
of kernel stack into the trace event ring buffer where userspace can
read it via tracefs.

Set CXL_HEADERLOG_SIZE to 64 and derive CXL_HEADERLOG_SIZE_U32 from it,
bringing all iomap readers into agreement on 16 dwords.  Userspace tools
such as rasdaemon have grown a dependency on the buggy 512-byte (128 u32)
header_log layout in the cxl_aer_uncorrectable_error trace event.  Add
CXL_HEADERLOG_TRACE_SIZE_U32 = 128 and use it for the trace event
__array and its memcpy to preserve that ABI.  Both callers now pass a
zero-filled u32[CXL_HEADERLOG_TRACE_SIZE_U32] staging buffer with only
the first CXL_HEADERLOG_SIZE_U32 (16) entries populated from hardware;
the remaining 112 u32s are zero-padded, keeping the 512-byte trace ring
buffer layout intact.

[ dj: Replaced 64 with SZ_64 per RichardC ]

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.