How severe is CVE-2021-30178?

CVE-2021-30178 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-30178 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-30178?

CVE-2021-30178 primarily affects Linux Linux Kernel. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-30178?

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

When was CVE-2021-30178 published?

CVE-2021-30178 was published on 2021-04-07 and last updated on 2026-06-17.

CVE-2021-30178

CVE-2021-30178 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. 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-476.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v2: 2.1
EPSS exploit prediction: 0% (22nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Linux Linux Kernel
Published: 2021-04-07
Last modified: 2026-06-17

Description

An issue was discovered in the Linux kernel through 5.11.11. synic_get in arch/x86/kvm/hyperv.c has a NULL pointer dereference for certain accesses to the SynIC Hyper-V context, aka CID-919f4ebc5987.

Frequently asked questions

What is CVE-2021-30178?: An issue was discovered in the Linux kernel through 5.11.11. synic_get in arch/x86/kvm/hyperv.c has a NULL pointer dereference for certain accesses to the SynIC Hyper-V context, aka CID-919f4ebc5987.
How severe is CVE-2021-30178?: CVE-2021-30178 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-30178 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-30178?: CVE-2021-30178 primarily affects Linux Linux Kernel. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-30178?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-30178 published?: CVE-2021-30178 was published on 2021-04-07 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

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