CVE-2026-53187
7.1 · HIGHOverview
CVE-2026-53187 is a high-severity vulnerability affecting linux linux_kernel. It was published on June 25, 2026 and has a CVSS 3.1 base score of 7.1 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.1, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
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.
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linux | linux_kernel | >= 6.17, < 6.18.36 | Affected |
Frequently Asked Questions
What is CVE-2026-53187?
CVE-2026-53187 is a high-severity vulnerability affecting linux linux_kernel. It was published on June 25, 2026 and has a CVSS 3.1 base score of 7.1 (HIGH).
How severe is CVE-2026-53187?
This vulnerability has a CVSS 3.1 base score of 7.1, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-53187?
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-53187?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-53187 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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