How severe is CVE-2018-19966?

CVE-2018-19966 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-19966 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-19966?

CVE-2018-19966 primarily affects Xen. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-19966?

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-2018-19966 published?

CVE-2018-19966 was published on 2018-12-08 and last updated on 2026-06-17.

CVE-2018-19966

CVE-2018-19966 is a high-severity vulnerability in Xen with a CVSS 3.x base score of 8.8. 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-436.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 7.2
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-436
Affected product: Xen
Published: 2018-12-08
Last modified: 2026-06-17

Description

An issue was discovered in Xen through 4.11.x allowing x86 PV guest OS users to cause a denial of service (host OS crash) or possibly gain host OS privileges because of an interpretation conflict for a union data structure associated with shadow paging. NOTE: this issue exists because of an incorrect fix for CVE-2017-15595.

Frequently asked questions

What is CVE-2018-19966?: An issue was discovered in Xen through 4.11.x allowing x86 PV guest OS users to cause a denial of service (host OS crash) or possibly gain host OS privileges because of an interpretation conflict for a union data structure associated with shadow paging. NOTE: this issue exists because of an incorrect fix for CVE-2017-15595.
How severe is CVE-2018-19966?: CVE-2018-19966 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-19966 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-19966?: CVE-2018-19966 primarily affects Xen. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-19966?: 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-2018-19966 published?: CVE-2018-19966 was published on 2018-12-08 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

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