CVE-2026-31788

HIGH EPSS 4.9%
Published Mar 25, 20263mo ago · Modified Jun 17, 20261w ago
8.2 CVSS 3.1
High
Find Similar
Published Mar 25, 2026 3mo ago
Last Modified Jun 17, 2026 1w ago

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)

CVSS Details

Base Score
8.2
Exploitability
1.5
Impact
6.0
Vector string
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required High
User Interaction None
Scope Changed
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
4.9% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Affected Products 15

VendorProductVersionRange
linuxlinux_kernel*≥2.6.37.1  –  <5.10.253
linuxlinux_kernel*≥5.11  –  <5.15.203
linuxlinux_kernel*≥5.16  –  <6.1.167
linuxlinux_kernel*≥6.2  –  <6.6.130
linuxlinux_kernel*≥6.7  –  <6.12.78
linuxlinux_kernel*≥6.13  –  <6.18.20
linuxlinux_kernel*≥6.19  –  <6.19.10
linuxlinux_kernel2.6.37any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any

References 14

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

Remediation

  • xenbits.xen.org http://xenbits.xen.org/xsa/advisory-482.html
    PatchThird Party Advisory
  • git.kernel.org https://git.kernel.org/stable/c/1879319d790f7d57622cdc22807b60ea78b56b6d
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/3ee5b9e3de4b8bdd74183d83205481c91a9effc8
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/453b8fb68f3641fea970db88b7d9a153ed2a37e8
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/4eb245ff0d33b618e097a2c23de5df56d4ad6969
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/78432d8f0372c71c518096395537fa12be7ff24e
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/87a803edb2ded911cb587c53bff179d2a2ed2a28
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/cbede2e833da1893afbea9b3ff29b5dda23a4a91
    Patch