Out-of-bounds Read Affecting kernel-rt-modules package, versions <0:4.18.0-553.171.1.rt7.512.el8_10


Severity

Recommended
high

Based on Rocky Linux security rating.

Threat Intelligence

EPSS
0.17% (6th percentile)

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  • Snyk IDSNYK-ROCKY8-KERNELRTMODULES-20551025
  • published7 Oct 2026
  • disclosed27 May 2026

Introduced: 27 May 2026

CVE-2026-45856  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

Upgrade Rocky-Linux:8 kernel-rt-modules to version 0:4.18.0-553.171.1.rt7.512.el8_10 or higher.
This issue was patched in RLSA-2026:75746.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-modules package and not the kernel-rt-modules package as distributed by Rocky-Linux. See How to fix? for Rocky-Linux:8 relevant fixed versions and status.

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

RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send

ib_uverbs_post_send() uses cmd.wqe_size from userspace without any validation before passing it to kmalloc() and using the allocated buffer as struct ib_uverbs_send_wr.

If a user provides a small wqe_size value (e.g., 1), kmalloc() will succeed, but subsequent accesses to user_wr->opcode, user_wr->num_sge, and other fields will read beyond the allocated buffer, resulting in an out-of-bounds read from kernel heap memory. This could potentially leak sensitive kernel information to userspace.

Additionally, providing an excessively large wqe_size can trigger a WARNING in the memory allocation path, as reported by syzkaller.

This is inconsistent with ib_uverbs_unmarshall_recv() which properly validates that wqe_size >= sizeof(struct ib_uverbs_recv_wr) before proceeding.

Add the same validation for ib_uverbs_post_send() to ensure wqe_size is at least sizeof(struct ib_uverbs_send_wr).

CVSS Base Scores

version 3.1