How severe is CVE-2018-19965?

CVE-2018-19965 has a CVSS 3.x base score of 5.6, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-19965 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-19965?

CVE-2018-19965 primarily affects Citrix Xenserver. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-19965?

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

When was CVE-2018-19965 published?

CVE-2018-19965 was published on 2018-12-08 and last updated on 2026-06-17.

CVE-2018-19965

CVE-2018-19965 is a medium-severity vulnerability in Citrix Xenserver with a CVSS 3.x base score of 5.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 5.6)
CVSS v2: 4.7
EPSS exploit prediction: 0% (33rd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Citrix Xenserver
Published: 2018-12-08
Last modified: 2026-06-17

Description

An issue was discovered in Xen through 4.11.x allowing 64-bit PV guest OS users to cause a denial of service (host OS crash) because #GP[0] can occur after a non-canonical address is passed to the TLB flushing code. NOTE: this issue exists because of an incorrect CVE-2017-5754 (aka Meltdown) mitigation.

Frequently asked questions

What is CVE-2018-19965?: An issue was discovered in Xen through 4.11.x allowing 64-bit PV guest OS users to cause a denial of service (host OS crash) because #GP[0] can occur after a non-canonical address is passed to the TLB flushing code. NOTE: this issue exists because of an incorrect CVE-2017-5754 (aka Meltdown) mitigation.
How severe is CVE-2018-19965?: CVE-2018-19965 has a CVSS 3.x base score of 5.6, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-19965 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-19965?: CVE-2018-19965 primarily affects Citrix Xenserver. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-19965?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-19965 published?: CVE-2018-19965 was published on 2018-12-08 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*
cpe:2.3:a:citrix:xenserver:7.0:*:*:*:*:*:*:*
cpe:2.3:a:citrix:xenserver:7.1:cu1:*:*:ltsr:*:*:*
cpe:2.3:a:citrix:xenserver:7.5:*:*:*:*:*:*:*
cpe:2.3:a:citrix:xenserver:7.6:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

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