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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-31788 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: xen/privcmd: restrict usage in unprivileged domU The Xen privcmd driver allows to issue arbitrary hypercalls from user space processes. This is normally no problem, as access is usually limited to root and the hypervisor will deny any hypercalls affecting other domains. In case the guest is booted using secure boot, however, the privcmd driver would be enabling a root user process to modify e.g. kernel memory contents, thus breaking the secure boot feature. The only known case where an unprivileged domU is really needing to use the privcmd driver is the case when it is acting as the device model for another guest. In this case all hypercalls issued via the privcmd driver will target that other guest. Fortunately the privcmd driver can already be locked down to allow only hypercalls targeting a specific domain, but this mode can be activated from user land only today. The target domain can be obtained from Xenstore, so when not running in dom0 restrict the privcmd driver to that target domain from the beginning, resolving the potential problem of breaking secure boot. This is XSA-482 --- V2: - defer reading from Xenstore if Xenstore isn't ready yet (Jan Beulich) - wait in open() if target domain isn't known yet - issue message in case no target domain found (Jan Beulich)


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
http://www.openwall.com/lists/oss-security/2026/03/24/2 CVE
http://www.openwall.com/lists/oss-security/2026/03/24/3 CVE
http://www.openwall.com/lists/oss-security/2026/03/24/4 CVE
http://www.openwall.com/lists/oss-security/2026/03/24/5 CVE
http://xenbits.xen.org/xsa/advisory-482.html CVE
https://git.kernel.org/stable/c/1879319d790f7d57622cdc22807b60ea78b56b6d kernel.org
https://git.kernel.org/stable/c/389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4 kernel.org
https://git.kernel.org/stable/c/78432d8f0372c71c518096395537fa12be7ff24e kernel.org
https://git.kernel.org/stable/c/87a803edb2ded911cb587c53bff179d2a2ed2a28 kernel.org
https://git.kernel.org/stable/c/cbede2e833da1893afbea9b3ff29b5dda23a4a91 kernel.org

Weakness Enumeration

CWE-ID CWE Name Source

Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-31788
NVD Published Date:
03/25/2026
NVD Last Modified:
03/25/2026
Source:
kernel.org