CVE-2016-7777

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Summary

CVECVE-2016-7777
StatePUBLISHED
Assignermitre
Source PriorityCVE Program / NVD first with legacy fallback
Published2016-10-07 14:59:10 UTC
Updated2026-05-06 22:30:45 UTC
DescriptionXen 4.7.x and earlier does not properly honor CR0.TS and CR0.EM, which allows local x86 HVM guest OS users to read or modify FPU, MMX, or XMM register state information belonging to arbitrary tasks on the guest by modifying an instruction while the hypervisor is preparing to emulate it.

Risk And Classification

Primary CVSS: v3.0 6.3 MEDIUM from [email protected]

CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

EPSS: 0.001220000 probability, percentile 0.307870000 (date 2026-05-07)

Problem Types: CWE-362 | n/a

VersionSourceTypeScoreSeverityVector
3.0[email protected]Primary6.3MEDIUMCVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
2.0[email protected]Primary3.3AV:L/AC:M/Au:N/C:P/I:P/A:N

CVSS v3.0 Breakdown

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

CVSS v2.0 Breakdown

Access Vector
Local
Access Complexity
Medium
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
None

AV:L/AC:M/Au:N/C:P/I:P/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Xen Xen All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Na N/a affected n/a Not specified

References

ReferenceSourceLinkTags
Xen Control Register Access Race Condition Lets Local Users on a Guest System Read or Modify Register State Data for Other Processes on the Guest System - SecurityTracker af854a3a-2127-422b-91ae-364da2661108 www.securitytracker.com Third Party Advisory, VDB Entry
CVE-2016-7777 - Citrix XenServer Security Update af854a3a-2127-422b-91ae-364da2661108 support.citrix.com
XSA-190 - Xen Security Advisories af854a3a-2127-422b-91ae-364da2661108 xenbits.xen.org Mitigation, Patch, Vendor Advisory
Xen CVE-2016-7777 Security Bypass Vulnerability af854a3a-2127-422b-91ae-364da2661108 www.securityfocus.com Third Party Advisory, VDB Entry
Xen: Multiple vulnerabilities (GLSA 201611-09) — Gentoo security af854a3a-2127-422b-91ae-364da2661108 security.gentoo.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Legacy QID Mappings

  • 500809 Alpine Linux Security Update for xen
  • 504552 Alpine Linux Security Update for xen

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