How severe is CVE-2021-45337?

CVE-2021-45337 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-2021-45337 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-2021-45337?

CVE-2021-45337 affects Avast Antivirus. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-45337?

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-2021-45337 published?

CVE-2021-45337 was published on 2021-12-27 and last updated on 2026-06-17.

CVE-2021-45337

CVE-2021-45337 is a high-severity vulnerability in Avast Antivirus 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.

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
Affected product: Avast Antivirus
Published: 2021-12-27
Last modified: 2026-06-17

Description

Privilege escalation vulnerability in the Self-Defense driver of Avast Antivirus prior to 20.8 allows a local user with SYSTEM privileges to gain elevated privileges by "hollowing" process wsc_proxy.exe which could lead to acquire antimalware (AM-PPL) protection.

Frequently asked questions

What is CVE-2021-45337?: Privilege escalation vulnerability in the Self-Defense driver of Avast Antivirus prior to 20.8 allows a local user with SYSTEM privileges to gain elevated privileges by "hollowing" process wsc_proxy.exe which could lead to acquire antimalware (AM-PPL) protection.
How severe is CVE-2021-45337?: CVE-2021-45337 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-2021-45337 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-2021-45337?: CVE-2021-45337 affects Avast Antivirus. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-45337?: 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-2021-45337 published?: CVE-2021-45337 was published on 2021-12-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:avast:antivirus:*:*:*:*:*:*:*:*

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