xen/privcmd: restrict usage in unprivileged domU (Linux Linux)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.19 % · percentile 9 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Linux
- NVD status
- Modified
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)
Weaknesses (CWE)
- CWE-862 — Missing Authorization
References
- https://git.kernel.org/stable/c/4eb245ff0d33b618e097a2c23de5df56d4ad6969
- https://git.kernel.org/stable/c/3ee5b9e3de4b8bdd74183d83205481c91a9effc8
- https://git.kernel.org/stable/c/87a803edb2ded911cb587c53bff179d2a2ed2a28
- https://git.kernel.org/stable/c/1879319d790f7d57622cdc22807b60ea78b56b6d
- https://git.kernel.org/stable/c/78432d8f0372c71c518096395537fa12be7ff24e
- https://git.kernel.org/stable/c/389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4
- https://git.kernel.org/stable/c/cbede2e833da1893afbea9b3ff29b5dda23a4a91
- https://git.kernel.org/stable/c/453b8fb68f3641fea970db88b7d9a153ed2a37e8
- http://xenbits.xen.org/xsa/advisory-482.html
- 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://www.openwall.com/lists/oss-security/2026/03/26/4
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 8.2 | CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H | Linux |
| CVSS 3.1 | HIGH 8.2 | CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H | NVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary) |
| CVSS 3.1 | HIGH 8.2 | CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H | NVD · nvd@nist.gov (Primary) |
European references
- ENISA EUVD · EUVD-2026-15401
- GCVE · GCVE-0-2026-31788
CERT-FR advisories
- CERTFR-2026-AVI-1229 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1093 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1066 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0985 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0954 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0926 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0696 — Multiples vulnérabilités dans le noyau Linux de Debian LTS · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0548 — Multiples vulnérabilités dans le noyau Linux de Debian · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0547 — Multiples vulnérabilités dans le noyau Linux de Debian LTS · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0546 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0520 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0497 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0347 — Vulnérabilité dans Xen · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 2.6.37.1 < 5.10.253cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.11 < 5.15.203cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.16 < 6.1.167cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.2 < 6.6.130cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.7 < 6.12.78cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.13 < 6.18.20cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.19 < 6.19.10cpe: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:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| Linux · Linux | affected 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b < 4eb245ff0d33b618e097a2c23de5df56d4ad6969 ; affected 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b < 3ee5b9e3de4b8bdd74183d83205481c91a9effc8 ; affected 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b < 87a803edb2ded911cb587c53bff179d2a2ed2a28 ; affected 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b < 1879319d790f7d57622cdc22807b60ea78b56b6d ; affected 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b < 78432d8f0372c71c518096395537fa12be7ff24e ; affected 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b < 389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4 |
| Linux · Linux | affected 2.6.37 ; unaffected 0 < 2.6.37 ; unaffected 5.10.253 ≤ 5.10.* ; unaffected 5.15.203 ≤ 5.15.* ; unaffected 6.1.167 ≤ 6.1.* ; unaffected 6.6.130 ≤ 6.6.* |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |