Answer in brief
CVE-2026-31788 records a High severity (CVSS 8.2) vulnerability in xen/privcmd: restrict usage in unprivileged domU. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1c5de1939c204bde9cce87f4eb3d26e9f9eb732b <4eb245ff0d33b618e097a2c23de5df56d4ad6969 || >=1c5de1939c204bde9cce87f4eb3d26e9f9eb732b <3ee5b9e3de4b8bdd74183d83205481c91a9effc8 || >=1c5de1939c204bde9cce87f4eb3d26e9f9eb732b <87a803edb2ded911cb587c53bff179d2a2ed2a28 || >=1c5de1939c204bde9cce87f4eb3d26e9f9eb732b <1879319d790f7d57622cdc22807b60ea78b56b6d || >=1c5de1939c204bde9cce87f4eb3d26e9f9eb732b <78432d8f0372c71c518096395537fa12be7ff24e || >=1c5de1939c204bde9cce87f4eb3d26e9f9eb732b <389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4 || >=1c5de1939c204bde9cce87f4eb3d26e9f9eb732b <cbede2e833da1893afbea9b3ff29b5dda23a4a91 || >=1c5de1939c204bde9cce87f4eb3d26e9f9eb732b <453b8fb68f3641fea970db88b7d9a153ed2a37e8 | 4eb245ff0d33b618e097a2c23de5df56d4ad6969, 3ee5b9e3de4b8bdd74183d83205481c91a9effc8, 87a803edb2ded911cb587c53bff179d2a2ed2a28, 1879319d790f7d57622cdc22807b60ea78b56b6d, 78432d8f0372c71c518096395537fa12be7ff24e, 389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4, cbede2e833da1893afbea9b3ff29b5dda23a4a91, 453b8fb68f3641fea970db88b7d9a153ed2a37e8 |
| Linux/Linuxgeneric | 2.6.37 | Not reported |
Published upstream
Mar 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 16, 2026
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)
Quoted source text, attributed separately from HOL analysis.