How severe is CVE-2016-6259?

CVE-2016-6259 has a CVSS 3.x base score of 6.2, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2016-6259 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-6259?

CVE-2016-6259 primarily affects Citrix Xenserver. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-6259?

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

When was CVE-2016-6259 published?

CVE-2016-6259 was published on 2016-08-02 and last updated on 2026-06-17.

CVE-2016-6259

CVE-2016-6259 is a medium-severity vulnerability in Citrix Xenserver with a CVSS 3.x base score of 6.2. 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-20.

Key facts

Severity: Medium (CVSS 3.x base score 6.2)
CVSS v2: 4.9
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Citrix Xenserver
Published: 2016-08-02
Last modified: 2026-06-17

Description

Xen 4.5.x through 4.7.x do not implement Supervisor Mode Access Prevention (SMAP) whitelisting in 32-bit exception and event delivery, which allows local 32-bit PV guest OS kernels to cause a denial of service (hypervisor and VM crash) by triggering a safety check.

Frequently asked questions

What is CVE-2016-6259?: Xen 4.5.x through 4.7.x do not implement Supervisor Mode Access Prevention (SMAP) whitelisting in 32-bit exception and event delivery, which allows local 32-bit PV guest OS kernels to cause a denial of service (hypervisor and VM crash) by triggering a safety check.
How severe is CVE-2016-6259?: CVE-2016-6259 has a CVSS 3.x base score of 6.2, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2016-6259 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-6259?: CVE-2016-6259 primarily affects Citrix Xenserver. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-6259?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2016-6259 published?: CVE-2016-6259 was published on 2016-08-02 and last updated on 2026-06-17.

References

Affected products (14)

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:4.5.3:*:*:*:*:*:*:*
cpe:2.3:o:xen:xen:4.6.0:*:*:*:*:*:*:*
cpe:2.3:o:xen:xen:4.6.1:*:*:*:*:*:*:*
cpe:2.3:o:xen:xen:4.6.3:*:*:*:*:*:*:*
cpe:2.3:o:xen:xen:4.7.0:*:*:*:*:*:*:*
cpe:2.3:a:citrix:xenserver:6.0:*:*:*:*:*:*:*
cpe:2.3:a:citrix:xenserver:6.0.2:*:*:*:*:*:*:*
cpe:2.3:a:citrix:xenserver:6.1:*:*:*:*:*:*:*
cpe:2.3:a:citrix:xenserver:6.2.0:sp1:*:*:*:*:*:*
cpe:2.3:a:citrix:xenserver:6.5.0:sp1:*:*:*:*:*:*
cpe:2.3:a:citrix:xenserver:7.0:*:*:*:*:*:*:*

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