How severe is CVE-2021-45335?

CVE-2021-45335 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-2021-45335 being actively exploited?

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

What products are affected by CVE-2021-45335?

CVE-2021-45335 affects Avast Antivirus. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-45335?

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-2021-45335 published?

CVE-2021-45335 was published on 2021-12-27 and last updated on 2026-06-17.

CVE-2021-45335

CVE-2021-45335 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. The underlying weakness is classified as CWE-276.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 7.2
EPSS exploit prediction: 0% (30th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-276
Affected product: Avast Antivirus
Published: 2021-12-27
Last modified: 2026-06-17

Description

Sandbox component in Avast Antivirus prior to 20.4 has an insecure permission which could be abused by local user to control the outcome of scans, and therefore evade detection or delete arbitrary system files.

Frequently asked questions

What is CVE-2021-45335?: Sandbox component in Avast Antivirus prior to 20.4 has an insecure permission which could be abused by local user to control the outcome of scans, and therefore evade detection or delete arbitrary system files.
How severe is CVE-2021-45335?: CVE-2021-45335 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-2021-45335 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-45335?: CVE-2021-45335 affects Avast Antivirus. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-45335?: 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-2021-45335 published?: CVE-2021-45335 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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