How severe is CVE-2018-19961?

CVE-2018-19961 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-19961 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-2018-19961?

CVE-2018-19961 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-2018-19961?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-19961 published?

CVE-2018-19961 was published on 2018-12-08 and last updated on 2026-06-17.

CVE-2018-19961

CVE-2018-19961 is a high-severity vulnerability in Citrix Xenserver with a CVSS 3.x base score of 7.8. 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-459.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 6.9
EPSS exploit prediction: 0% (33rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-459
Affected product: Citrix Xenserver
Published: 2018-12-08
Last modified: 2026-06-17

Description

An issue was discovered in Xen through 4.11.x on AMD x86 platforms, possibly allowing guest OS users to gain host OS privileges because TLB flushes do not always occur after IOMMU mapping changes.

Frequently asked questions

What is CVE-2018-19961?: An issue was discovered in Xen through 4.11.x on AMD x86 platforms, possibly allowing guest OS users to gain host OS privileges because TLB flushes do not always occur after IOMMU mapping changes.
How severe is CVE-2018-19961?: CVE-2018-19961 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-19961 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-2018-19961?: CVE-2018-19961 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-2018-19961?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-19961 published?: CVE-2018-19961 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:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
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:*:*:*:*:*:*:*

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CVE-2017-12137 — High (CVSS 8.8): arch/x86/mm.c in Xen allows local PV guest OS users to gain host OS privileges via vectors related to map_grant_ref.
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