Is CVE-2026-31651 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-31651 being exploited in the wild.

How severe is CVE-2026-31651?

Medium severity, with a CVSS score of 5.5, published 24 April 2026.

Which products and versions are affected?

Linux Kernel 3.0 to 6.14; Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5, V3.1.6.

Is there a fix for CVE-2026-31651?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-31651 attacked?

It is attacked with local access, in an operating system.

Am I affected by CVE-2026-31651?

Check whether you run Linux Kernel or Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-31651: Linux Kernel NULL pointer dereference in vub300 MMC driver

CVE-2026-31651 · Severity: medium · CVSS 5.5 · Published 2026-04-24

A vulnerability in the Linux kernel's VUB300 USB-to-SD driver can cause a system crash when a device is disconnected. This affects systems using specific SD/MMC hardware interfaces, including certain industrial Siemens controllers. An attacker with local access could exploit this to cause a denial-of-service, potentially disrupting operations or industrial processes.

Technologies: Linux Kernel, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP. Vendors: Linux, Siemens.

Quick answers

Is CVE-2026-31651 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-31651 being exploited in the wild.
How severe is CVE-2026-31651?: Medium severity, with a CVSS score of 5.5, published 24 April 2026.
Which products and versions are affected?: Linux Kernel 3.0 to 6.14; Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5, V3.1.6.
Is there a fix for CVE-2026-31651?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-31651 attacked?: It is attacked with local access, in an operating system.
Am I affected by CVE-2026-31651?: Check whether you run Linux Kernel or Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A race condition or improper cleanup sequence exists in the vub300_disconnect function within drivers/mmc/host/vub300.c. The driver was dropping its reference to driver data (kref_put) before deregistering the MMC host (mmc_remove_host), leading to a NULL pointer dereference or use-after-free if the host was accessed during the teardown process. A local attacker can trigger this by initiating a device disconnect, resulting in a kernel oops and denial of service. Patches have been backported to multiple stable kernel branches (3.0+).

Affected products

Linux Linux Kernel 3.0 to 6.14
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5, V3.1.6

Timeline

2026-03-27: other: Patch authored by Johan Hovold
2026-04-24: disclosed: CVE published

References

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