# CVE-2026-53187: linux: In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Validate cpu_id against nr_cpu_ids in... CVE-2026-53187 is fixed in 20 products on 1 platform, first by DEBIAN-CVE-2026-53187, released June 28, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-53187 - Priority: High - CVSS: 7.1 (high) - EPSS: 0.0016 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jun 25, 2026 ## 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.18 amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel-livepatch-6.18.36-69.134 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | linux Debian 14 | 7.0.13-1 | [DEBIAN-CVE-2026-53187](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53187.md) | Jun 28, 2026 | | Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.36-69.134.amzn2023 | [ALAS2023-2026-1925](https://patchblox.com/security/data/fix/linux/alas2023-2026-1925.md) | Jul 6, 2026 | --- Data as of 2026-11-09T01:18:40Z UTC. 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