CVE-2026-31788

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-31788
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)

8.2 /10

CVSS v3 : HIGH

V3 Legend

Vector :

Exploitability : 1.5 / Impact : 6.0

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required HIGH

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope CHANGED

References
Link Resource
https://git.kernel.org/stable/c/1879319d790f7d57622cdc22807b60ea78b56b6d Patch
https://git.kernel.org/stable/c/389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4 Patch
https://git.kernel.org/stable/c/3ee5b9e3de4b8bdd74183d83205481c91a9effc8 Patch
https://git.kernel.org/stable/c/453b8fb68f3641fea970db88b7d9a153ed2a37e8 Patch
https://git.kernel.org/stable/c/4eb245ff0d33b618e097a2c23de5df56d4ad6969 Patch
https://git.kernel.org/stable/c/78432d8f0372c71c518096395537fa12be7ff24e Patch
https://git.kernel.org/stable/c/87a803edb2ded911cb587c53bff179d2a2ed2a28 Patch
https://git.kernel.org/stable/c/cbede2e833da1893afbea9b3ff29b5dda23a4a91 Patch
http://www.openwall.com/lists/oss-security/2026/03/24/2 Mailing List
http://www.openwall.com/lists/oss-security/2026/03/24/3 Mailing List
http://www.openwall.com/lists/oss-security/2026/03/24/4 Mailing List
http://www.openwall.com/lists/oss-security/2026/03/24/5 Mailing List
http://www.openwall.com/lists/oss-security/2026/03/26/4 Mailing List
http://xenbits.xen.org/xsa/advisory-482.html Patch Third Party Advisory
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.37:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*
History

24 Apr 2026, 15:19

Type Values Removed Values Added
CPE cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.37:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*
CWE NVD-CWE-noinfo
First Time Linux
Linux linux Kernel
References () https://git.kernel.org/stable/c/1879319d790f7d57622cdc22807b60ea78b56b6d - () https://git.kernel.org/stable/c/1879319d790f7d57622cdc22807b60ea78b56b6d - Patch
References () https://git.kernel.org/stable/c/389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4 - () https://git.kernel.org/stable/c/389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4 - Patch
References () https://git.kernel.org/stable/c/3ee5b9e3de4b8bdd74183d83205481c91a9effc8 - () https://git.kernel.org/stable/c/3ee5b9e3de4b8bdd74183d83205481c91a9effc8 - Patch
References () https://git.kernel.org/stable/c/453b8fb68f3641fea970db88b7d9a153ed2a37e8 - () https://git.kernel.org/stable/c/453b8fb68f3641fea970db88b7d9a153ed2a37e8 - Patch
References () https://git.kernel.org/stable/c/4eb245ff0d33b618e097a2c23de5df56d4ad6969 - () https://git.kernel.org/stable/c/4eb245ff0d33b618e097a2c23de5df56d4ad6969 - Patch
References () https://git.kernel.org/stable/c/78432d8f0372c71c518096395537fa12be7ff24e - () https://git.kernel.org/stable/c/78432d8f0372c71c518096395537fa12be7ff24e - Patch
References () https://git.kernel.org/stable/c/87a803edb2ded911cb587c53bff179d2a2ed2a28 - () https://git.kernel.org/stable/c/87a803edb2ded911cb587c53bff179d2a2ed2a28 - Patch
References () https://git.kernel.org/stable/c/cbede2e833da1893afbea9b3ff29b5dda23a4a91 - () https://git.kernel.org/stable/c/cbede2e833da1893afbea9b3ff29b5dda23a4a91 - Patch
References () http://www.openwall.com/lists/oss-security/2026/03/24/2 - () http://www.openwall.com/lists/oss-security/2026/03/24/2 - Mailing List
References () http://www.openwall.com/lists/oss-security/2026/03/24/3 - () http://www.openwall.com/lists/oss-security/2026/03/24/3 - Mailing List
References () http://www.openwall.com/lists/oss-security/2026/03/24/4 - () http://www.openwall.com/lists/oss-security/2026/03/24/4 - Mailing List
References () http://www.openwall.com/lists/oss-security/2026/03/24/5 - () http://www.openwall.com/lists/oss-security/2026/03/24/5 - Mailing List
References () http://www.openwall.com/lists/oss-security/2026/03/26/4 - () http://www.openwall.com/lists/oss-security/2026/03/26/4 - Mailing List
References () http://xenbits.xen.org/xsa/advisory-482.html - () http://xenbits.xen.org/xsa/advisory-482.html - Patch, Third Party Advisory

18 Apr 2026, 09:16

Type Values Removed Values Added
References
  • () https://git.kernel.org/stable/c/3ee5b9e3de4b8bdd74183d83205481c91a9effc8 -
  • () https://git.kernel.org/stable/c/4eb245ff0d33b618e097a2c23de5df56d4ad6969 -

02 Apr 2026, 15:16

Type Values Removed Values Added
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 8.2

30 Mar 2026, 08:16

Type Values Removed Values Added
References
  • () https://git.kernel.org/stable/c/453b8fb68f3641fea970db88b7d9a153ed2a37e8 -

26 Mar 2026, 17:16

Type Values Removed Values Added
References
  • () http://www.openwall.com/lists/oss-security/2026/03/26/4 -
Summary
  • (es) En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta: xen/privcmd: restringir el uso en domU no privilegiado El controlador Xen privcmd permite emitir hiperllamadas arbitrarias desde procesos de espacio de usuario. Esto normalmente no es un problema, ya que el acceso suele estar limitado a root y el hipervisor denegará cualquier hiperllamada que afecte a otros dominios. En caso de que el invitado se inicie usando arranque seguro, sin embargo, el controlador privcmd estaría permitiendo que un proceso de usuario root modifique, por ejemplo, el contenido de la memoria del kernel, rompiendo así la característica de arranque seguro. El único caso conocido en el que un domU no privilegiado realmente necesita usar el controlador privcmd es el caso en el que actúa como modelo de dispositivo para otro invitado. En este caso, todas las hiperllamadas emitidas a través del controlador privcmd se dirigirán a ese otro invitado. Afortunadamente, el controlador privcmd ya puede ser bloqueado para permitir solo hiperllamadas dirigidas a un dominio específico, pero este modo solo puede activarse desde el espacio de usuario hoy. El dominio objetivo puede obtenerse de Xenstore, por lo que cuando no se ejecute en dom0, restrinja el controlador privcmd a ese dominio objetivo desde el principio, resolviendo el problema potencial de romper el arranque seguro. Esto es XSA-482 --- V2: - aplazar la lectura de Xenstore si Xenstore aún no está listo (Jan Beulich) - esperar en open() si el dominio objetivo aún no se conoce - emitir mensaje en caso de no encontrar dominio objetivo (Jan Beulich)

25 Mar 2026, 12:16

Type Values Removed Values Added
References
  • () http://www.openwall.com/lists/oss-security/2026/03/24/2 -
  • () http://www.openwall.com/lists/oss-security/2026/03/24/3 -
  • () http://www.openwall.com/lists/oss-security/2026/03/24/4 -
  • () http://www.openwall.com/lists/oss-security/2026/03/24/5 -
  • () http://xenbits.xen.org/xsa/advisory-482.html -

25 Mar 2026, 11:16

Type Values Removed Values Added
New CVE
Information

Published : 2026-03-25 11:16

Updated : 2026-06-17 10:34

NVD link : CVE-2026-31788

Mitre link : CVE-2026-31788

CVE.ORG link : CVE-2026-31788

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
NVD-CWE-noinfo