CVE Catalog

CVE-2026-31786

High
Published: Translated: NVD NIST

Summary

A buffer overflow vulnerability has been identified in the Linux kernel in the file drivers/xen/sys-hypervisor.c. The issue arises because the build id returned by HYPERVISOR_xen_version(XENVER_build_id) is not NUL terminated, leading to memory overflow.

Risk Assessment

Exploitation of this vulnerability could lead to unauthorized memory access, posing a risk of system destabilization or execution of malicious code. Organizations should be aware of the potential security threats to their virtualization systems.

Recommendation

It is recommended to update the Linux kernel to the latest version that includes fixes for this vulnerability. Additionally, consider using memcpy instead of sprintf in the code to avoid similar issues in the future.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: Buffer overflow in drivers/xen/sys-hypervisor.c The build id returned by HYPERVISOR_xen_version(XENVER_build_id) is neither NUL terminated nor a string. The first causes a buffer overflow as sprintf in buildid_show will read and copy till it finds a NUL. 00000000 f4 91 51 f4 dd 38 9e 9d 65 47 52 eb 10 71 db 50 |..Q..8..eGR..q.P| 00000010 b9 a8 01 42 6f 2e 32 |...Bo.2| 00000017 So use a memcpy instead of sprintf to have the correct value: 00000000 f4 91 51 f4 dd 00 9e 9d 65 47 52 eb 10 71 db 50 |..Q.....eGR..q.P| 00000010 b9 a8 01 42 |...B| 00000014 (the above have a hack to embed a zero inside and check it's returned correctly). This is XSA-485 / CVE-2026-31786

Vulnerability data from NVD (NIST) · CISA KEV · EPSS