CVE-2026-31542: 
Linux Kernel vulnerability analysis and mitigation

CVE-2026-31542 is a denial-of-service vulnerability in the Linux kernel's x86 UV (Ultra Violet) platform subsystem, caused by improper handling of deconfigured sockets during UV hub info structure allocation. When a socket is deconfigured, it is mapped to SOCK_EMPTY (0xffff), which triggers a kernel panic during memory allocation. The vulnerability affects Linux kernel versions 6.5 through 6.6.130 (exclusive), 6.7 through 6.12.78 (exclusive), 6.13 through 6.18.20 (exclusive), 6.19 through 6.19.10 (exclusive), and 7.0 release candidates. It was published on April 24, 2026, and carries a CVSS v3.1 base score of 5.5 (Medium) (Red Hat CVE, Feedly).

The root cause is classified as CWE-386 (Symbolic Name not Mapping to Correct Object): when a socket is deconfigured in the UV platform, it is assigned the sentinel value SOCK_EMPTY (0xffff), which is not a valid NUMA node identifier. The UV hub info allocation code does not account for this invalid mapping, causing it to attempt memory allocation using an invalid node value and triggering a kernel panic. The fix replaces the invalid SOCK_EMPTY value with NUMA_NO_NODE, allowing the allocator to fall back to a valid node. This is a local vulnerability requiring low privileges and no user interaction to trigger (Red Hat CVE, Kernel Patch).

Successful exploitation causes a kernel panic, resulting in a complete system crash and denial of service. The impact is limited to availability — confidentiality and integrity of data are not affected. The vulnerability is relevant only to systems running on x86 UV (SGI/HPE UV) hardware platforms with the affected kernel versions, limiting its scope to specialized high-performance computing environments (Red Hat CVE, Feedly).

There is no public proof-of-concept exploit and no evidence of in-the-wild exploitation as of the time of this report. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.018%, reflecting a very low probability of exploitation in the near term. Exploitation requires local access with low privileges on a system running affected kernel versions on UV platform hardware (Feedly).

Patches are available in the following Linux kernel stable releases: 6.6.130, 6.12.78, 6.18.20, 6.19.10, and 7.0. Administrators should upgrade to the appropriate patched version for their kernel branch as soon as possible. As an interim measure, restricting local access privileges on affected UV platform systems can reduce exploitation risk. Monitor affected systems for unexpected kernel panic events as a potential indicator of triggering conditions (Red Hat CVE, Kernel Patch).