How severe is CVE-2021-45336?

CVE-2021-45336 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-2021-45336 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-45336?

CVE-2021-45336 affects Avast Antivirus. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-45336?

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-2021-45336 published?

CVE-2021-45336 was published on 2021-12-27 and last updated on 2026-06-17.

CVE-2021-45336

CVE-2021-45336 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% (36th 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 Sandbox component of Avast Antivirus prior to 20.4 allows a local sandboxed code to gain elevated privileges by using system IPC interfaces which could lead to exit the sandbox and acquire SYSTEM privileges.

Frequently asked questions

What is CVE-2021-45336?: Privilege escalation vulnerability in the Sandbox component of Avast Antivirus prior to 20.4 allows a local sandboxed code to gain elevated privileges by using system IPC interfaces which could lead to exit the sandbox and acquire SYSTEM privileges.
How severe is CVE-2021-45336?: CVE-2021-45336 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-2021-45336 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-45336?: CVE-2021-45336 affects Avast Antivirus. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-45336?: 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-2021-45336 published?: CVE-2021-45336 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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