CVE-2026-31788xen/privcmd: restrict usage in unprivileged domU
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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
- 8.2 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Analyzed
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b before 4eb245ff0d33b618e097a2c23de5df56d4ad6969; from 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b before 3ee5b9e3de4b8bdd74183d83205481c91a9effc8; from 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b before 87a803edb2ded911cb587c53bff179d2a2ed2a28; from 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b before 1879319d790f7d57622cdc22807b60ea78b56b6d; from 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b before 78432d8f0372c71c518096395537fa12be7ff24e; from 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b before 389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4; from 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b before cbede2e833da1893afbea9b3ff29b5dda23a4a91; from 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b before 453b8fb68f3641fea970db88b7d9a153ed2a37e8 | CNA record |
linux linux_kernel linux:linux_kernel | from 2.6.37.1 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.167; from 6.2 before 6.6.130; from 6.7 before 6.12.78; from 6.13 before 6.18.20; from 6.19 before 6.19.10; 2.6.37; and 7 more ranges | NVD |
References
- https://git.kernel.org/stable/c/4eb245ff0d33b618e097a2c23de5df56d4ad6969patch
- https://git.kernel.org/stable/c/3ee5b9e3de4b8bdd74183d83205481c91a9effc8patch
- https://git.kernel.org/stable/c/87a803edb2ded911cb587c53bff179d2a2ed2a28patch
- https://git.kernel.org/stable/c/1879319d790f7d57622cdc22807b60ea78b56b6dpatch
- https://git.kernel.org/stable/c/78432d8f0372c71c518096395537fa12be7ff24epatch
- https://git.kernel.org/stable/c/389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4patch
- https://git.kernel.org/stable/c/cbede2e833da1893afbea9b3ff29b5dda23a4a91patch
- https://git.kernel.org/stable/c/453b8fb68f3641fea970db88b7d9a153ed2a37e8patch
- http://www.openwall.com/lists/oss-security/2026/03/24/2mailing-list
- http://www.openwall.com/lists/oss-security/2026/03/24/3mailing-list
- http://www.openwall.com/lists/oss-security/2026/03/24/4mailing-list
- http://www.openwall.com/lists/oss-security/2026/03/24/5mailing-list
- http://www.openwall.com/lists/oss-security/2026/03/26/4mailing-list
- http://xenbits.xen.org/xsa/advisory-482.htmlpatch, third-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.