CVE-2016-1571

CVE-2016-1571 is a medium-severity vulnerability in Citrix Xenserver with a CVSS 3.x base score of 6.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-17.

Key facts

• Severity: Medium (CVSS 3.x base score 6.3)
• CVSS v2: 4.7
• EPSS exploit prediction: 1% (66th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-17
• Affected product: Citrix Xenserver
• Published: 2016-01-22
• Last modified: 2026-06-17

Description

The paging_invlpg function in include/asm-x86/paging.h in Xen 3.3.x through 4.6.x, when using shadow mode paging or nested virtualization is enabled, allows local HVM guest users to cause a denial of service (host crash) via a non-canonical guest address in an INVVPID instruction, which triggers a hypervisor bug check.

Frequently asked questions

What is CVE-2016-1571?

The paging_invlpg function in include/asm-x86/paging.h in Xen 3.3.x through 4.6.x, when using shadow mode paging or nested virtualization is enabled, allows local HVM guest users to cause a denial of service (host crash) via a non-canonical guest address in an INVVPID instruction, which triggers a hypervisor bug check.

How severe is CVE-2016-1571?

CVE-2016-1571 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2016-1571 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-1571?

CVE-2016-1571 primarily affects Citrix Xenserver. In total, 37 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-1571?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2016-1571 published?

CVE-2016-1571 was published on 2016-01-22 and last updated on 2026-06-17.

References

• http://support.citrix.com/article/CTX205496
• http://www.debian.org/security/2016/dsa-3519
• http://www.securitytracker.com/id/1034745
• http://xenbits.xen.org/xsa/advisory-168.html

Affected products (37)

• cpe:2.3:a:citrix:xenserver:*:sp1:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:3.3.0:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:3.3.1:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:3.3.2:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:3.4.0:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:3.4.1:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:3.4.2:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:3.4.3:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:3.4.4:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.1.0:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.1.1:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.1.2:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.1.3:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.1.4:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.1.5:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.1.6:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.1.6.1:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.2.0:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.2.1:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.2.2:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.2.3:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.2.4:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.2.5:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.3.0:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.3.1:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.3.2:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.3.3:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.3.4:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.4.0:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.4.0:rc1:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.4.1:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.4.2:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.4.3:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.5.0:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.5.1:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.5.2:*:*:*:*:*:*:*
• cpe:2.3:o:xen:xen:4.6.0:*:*:*:*:*:*:*

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