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CVE-2016-10013 Xen CVE debrief

CVE-2016-10013 is a high-severity Xen vulnerability affecting 64-bit x86 HVM guests. According to the CVE description, mishandling of SYSCALL singlestep during emulation can let a local guest user gain privileges. This is primarily a concern for environments that run affected Xen releases and expose 64-bit x86 HVM guest workloads to potentially untrusted users. The CVE was published on 2017-01-26.

Vendor
Xen
Product
CVE-2016-10013
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2017-01-26
Original CVE updated
2026-05-13
Advisory published
2017-01-26
Advisory updated
2026-05-13

Who should care

Xen administrators, virtualization platform owners, and security teams responsible for 64-bit x86 HVM guest environments on affected Xen versions. Systems that allow local guest logins or untrusted workloads inside guests should treat this as a priority issue.

Technical summary

The vulnerability is described as a mishandling of SYSCALL singlestep during emulation in Xen. The impact is local privilege gain by a 64-bit x86 HVM guest OS user. NVD assigns CVSS 3.0 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and maps the affected product range to Xen through 4.8.0, while the CVE description states through 4.8.x.

Defensive priority

High for any Xen deployment running affected 64-bit x86 HVM guests. The issue requires local access inside the guest, but the impact is serious enough to justify prompt patching and guest-facing exposure review.

Recommended defensive actions

  • Confirm whether your Xen deployment is within the affected range identified by NVD and the CVE description.
  • Prioritize upgrading or applying the vendor-provided Xen fix referenced in XSA-204.
  • Review which guest workloads run on affected 64-bit x86 HVM instances and reduce untrusted local access where practical.
  • Coordinate maintenance windows for host and guest patching, since the flaw is in virtualization/emulation handling.
  • Use downstream advisories, such as Debian DSA-3847, to identify distribution-specific remediation guidance.

Evidence notes

The debrief is based on the CVE description, NVD metadata, and the vendor advisory reference. The supplied corpus states that Xen through 4.8.x allows local 64-bit x86 HVM guest OS users to gain privileges via mishandling of SYSCALL singlestep during emulation. NVD further lists the vulnerable CPE range as Xen through 4.8.0 and rates the issue CVSS 3.0 HIGH (7.8). The vendor advisory reference is XSA-204; Debian DSA-3847 is listed as a downstream advisory reference.

Official resources

Published by the CVE record on 2017-01-26. The CVE and NVD records were modified later, but those later dates do not change the original issue date.