CVE-2025-40300 Affecting dlm-kmp-default package, versions <6.4.0-150600.23.73.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.05% (14th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-SLES156-DLMKMPDEFAULT-13583483
  • published16 Oct 2025
  • disclosed15 Oct 2025

Introduced: 15 Oct 2025

NewCVE-2025-40300  (opens in a new tab)

How to fix?

Upgrade SLES:15.6 dlm-kmp-default to version 6.4.0-150600.23.73.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream dlm-kmp-default package and not the dlm-kmp-default package as distributed by SLES. See How to fix? for SLES:15.6 relevant fixed versions and status.

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

x86/vmscape: Add conditional IBPB mitigation

VMSCAPE is a vulnerability that exploits insufficient branch predictor isolation between a guest and a userspace hypervisor (like QEMU). Existing mitigations already protect kernel/KVM from a malicious guest. Userspace can additionally be protected by flushing the branch predictors after a VMexit.

Since it is the userspace that consumes the poisoned branch predictors, conditionally issue an IBPB after a VMexit and before returning to userspace. Workloads that frequently switch between hypervisor and userspace will incur the most overhead from the new IBPB.

This new IBPB is not integrated with the existing IBPB sites. For instance, a task can use the existing speculation control prctl() to get an IBPB at context switch time. With this implementation, the IBPB is doubled up: one at context switch and another before running userspace.

The intent is to integrate and optimize these cases post-embargo.

[ dhansen: elaborate on suboptimal IBPB solution ]

CVSS Base Scores

version 3.1