Out-of-bounds Write Affecting linux-qemu-melange package, versions <6.18.38-r0


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.12% (3rd percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-LINUXQEMUMELANGE-17949814
  • published11 Jul 2026
  • disclosed25 Jun 2026

Introduced: 25 Jun 2026

CVE-2026-53187  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade Chainguard linux-qemu-melange to version 6.18.38-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-qemu-melange package and not the linux-qemu-melange package as distributed by Chainguard. See How to fix? for Chainguard relevant fixed versions and status.

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

RDMA/core: Validate cpu_id against nr_cpu_ids in DMAH alloc

The cpu_id attribute supplied by user space through UVERBS_ATTR_ALLOC_DMAH_CPU_ID is passed directly to cpumask_test_cpu() without first verifying that the value is within the valid CPU range.

Passing such untrusted data to cpumask_test_cpu() may lead to an out-of-bounds read of the underlying cpumask bitmap: the helper expands to a test_bit() that indexes the bitmap by cpu_id / BITS_PER_LONG with no bound check.

In addition, on kernels built with CONFIG_DEBUG_PER_CPU_MAPS it trips the WARN_ON_ONCE() in cpumask_check(); combined with panic_on_warn this turns a bad user input into a machine reboot.

Reject any cpu_id that is not smaller than nr_cpu_ids with -EINVAL before it is used.

Reported by Smatch.

CVSS Base Scores

version 3.1