CVE-2026-31564: 
Linux Debian vulnerability analysis and mitigation

CVE-2026-31564 is a denial-of-service vulnerability in the Linux kernel's LoongArch KVM implementation, specifically in the kvm_eiointc_regs_access() function. The flaw stems from an incorrect type conversion during register base address calculation, where a u64 array base address is not properly cast to void * before adding an offset, resulting in improper address computation. Affected versions include Linux kernel 6.19, 6.19.1 through 6.19.10, and 7.0-rc1 through 7.0-rc7. It was published on April 24, 2026, with a CVSS v3.1 base score of 5.5 (Medium) (Red Hat Advisory, Red Hat Bugzilla).

The root cause is classified as CWE-681 (Incorrect Conversion between Numeric Types). In kvm_eiointc_regs_access(), the register base address is computed by adding an absolute offset to a u64-typed array base address; because the base is not first cast to void *, pointer arithmetic is performed incorrectly, leading to an improper memory address being accessed. This is a local attack vector requiring low privileges and no user interaction, exploitable by a guest or local user on a LoongArch system running an affected kernel with KVM enabled. No public proof-of-concept exploit code has been identified (Red Hat Advisory, Red Hat Bugzilla).

Successful exploitation can cause memory corruption within the KVM subsystem, leading to a denial of service (system crash or instability) on LoongArch architecture hosts. The vulnerability has no confidentiality or integrity impact; only availability is affected. The scope is limited to the local system, and there is no evidence of potential for lateral movement or data exfiltration (Red Hat Advisory).

There is no known public proof-of-concept exploit and no evidence of in-the-wild exploitation at this time. 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 (Red Hat Advisory).

The vulnerability is fixed in Linux kernel version 6.19.11 and later stable releases. Patches are available via two commits in the stable kernel git repository: 6bcfb7f46d667b04bd1a1169ccedf5fb699c60df and c4f0a9481cf0dd7c71a07484bc98f2570fdb3a82. Systems running kernel 6.19.1 through 6.19.10 or 7.0-rc1 through 7.0-rc7 on LoongArch hardware should be updated to 6.19.11 or a subsequent stable release as soon as possible. No configuration-based workaround is available; patching is the only remediation (Red Hat Bugzilla, Kernel Patch 1, Kernel Patch 2).