Xen 4.0.x through 4.7.x mishandle x86 task switches to VM86 mode, which allows local 32-bit x86 HVM guest OS users to gain privileges or cau
Xen 4.0.x through 4.7.x mishandle x86 task switches to VM86 mode, which allows local 32-bit x86 HVM guest OS users to gain privileges or cause a denial of service (guest OS crash) by leveraging a guest operating system that uses hardware task switching and allows a new task to start in VM86 mode.
- Published
- Jan 23, 2017
- Updated
- Jun 16, 2026
- EPSS
- 0.5% · 37th percentile
- CWE
- CWE-264
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Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
Affected systems
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- citrix xenserver6.0.2
- citrix xenserver6.2.0
- citrix xenserver6.5
- citrix xenserver7.0
- xen xen4.0.0
- xen xen4.0.1
- xen xen4.0.2
- xen xen4.0.3
- xen xen4.0.4
- xen xen4.1.0
- xen xen4.1.1
- xen xen4.1.2
- xen xen4.1.3
- xen xen4.1.4
- xen xen4.1.5
- xen xen4.1.6.1
- xen xen4.2.0
- xen xen4.2.1
- xen xen4.2.2
- xen xen4.2.3
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.10 | xen | before 4.7.1-r1 | 4.7.1-r1 |
| Debian:12 | xen | before 4.8.0-1 | 4.8.0-1 |
| Debian:7 | xen | before 4.1.6.lts1-4 | 4.1.6.lts1-4 |
| Debian:8 | xen | before 4.4.1-9+deb8u8 | 4.4.1-9+deb8u8 |
| openSUSE:Tumbleweed | xen | before 4.15.1_01-1.2 | 4.15.1_01-1.2 |
| SUSE:Linux Enterprise Desktop 12 SP1 | xen | before 4.5.5_02-22.3.1 | 4.5.5_02-22.3.1 |
| SUSE:Linux Enterprise Desktop 12 SP2 | xen | before 4.7.1_02-25.1 | 4.7.1_02-25.1 |
| SUSE:Linux Enterprise Server 11 SP2-LTSS | xen | before 4.1.6_08-32.1 | 4.1.6_08-32.1 |
| SUSE:Linux Enterprise Server for SAP Applications 12 | xen | before 4.4.4_05-22.25.1 | 4.4.4_05-22.25.1 |
| SUSE:Linux Enterprise Software Development Kit 11 SP4 | xen | before 4.4.4_10-43.5 | 4.4.4_10-43.5 |
| SUSE:OpenStack Cloud 5 | xen | before 4.2.5_21-30.1 | 4.2.5_21-30.1 |
Same product
xen: all recordsOther highest-scoring records for the same primary product.
- CVE-2017-10921The grant-table feature in Xen through 4.8.x does not ensure sufficient type counts for a GNTMAP_device_map and GNTMAP_host_map mapping, whi41Plan
- CVE-2017-10920The grant-table feature in Xen through 4.8.x mishandles a GNTMAP_device_map and GNTMAP_host_map mapping, when followed by only a GNTMAP_host41Plan
- CVE-2017-10918Xen through 4.8.x does not validate memory allocations during certain P2M operations, which allows guest OS users to obtain privileged host 41Plan
- CVE-2017-10912Xen through 4.8.x mishandles page transfer, which allows guest OS users to obtain privileged host OS access, aka XSA-217.41Plan
- CVE-2015-8104The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a denial of service (host O41Plan
- CVE-2015-5165The C+ mode offload emulation in the RTL8139 network card device model in QEMU, as used in Xen 4.5.x and earlier, allows remote attackers to41Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:xen | 4.7.1-r1 · Alpine:v3.10 | Package registry (OSV) |
| debian:xen | 4.8.0-1 · Debian:12 | Package registry (OSV) |
| opensuse:xen | 4.15.1_01-1.2 · openSUSE:Tumbleweed | Package registry (OSV) |
| suse:xen | 4.1.6_08-32.1 · SUSE:Linux Enterprise Server 11 SP2-LTSS | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-264 · Permissions, Privileges, and Access ControlsCVSS vector
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- www.securityfocus.com/bid/94470
- www.securitytracker.com/id/1037341
- xenbits.xen.org/xsa/advisory-192.html
- security.gentoo.org/glsa/201612-56
- support.citrix.com/article/CTX218775
Vendor advisories and official records. Exploit/PoC links are deliberately left out.