What is CVE-2022-4291?

CVE-2022-4291 is a high-severity vulnerability in Avast Script Shield, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.7/10. Published 2022-12-08.

How severe is CVE-2022-4291?

High severity. CVSS v3 base score is 7.7 out of 10.

Buffer overflow in Avast Script Shield

CVE-2022-4291

The aswjsflt.dll library from Avast Antivirus windows contained a potentially exploitable heap corruption vulnerability that could enable an attacker to bypass the sandbox of the application it was loaded into, if applicable. This issue was fixed in version 18.0.1478 of the Script Shield Component.

Vulnerability class: Buffer Overflow

Published 2022-12-08 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L.

EPSS exploit prediction

EPSS: 0.004 (35.1th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000

Affected products

Avast Script Shield
Nortonlifelock Avast Antivirus — versions 0

Weakness classification (CWE)

References

support.norton.com/sp/static/external/tools/security-advisories.html (Vendor Advisory)

Frequently asked questions

What is CVE-2022-4291?: CVE-2022-4291 is a high-severity vulnerability in Avast Script Shield, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.7/10. Published 2022-12-08.
How severe is CVE-2022-4291?: High severity. CVSS v3 base score is 7.7 out of 10.