CVE intelligence and bounded remediation
CVE-2019-18894 — Avast Premium Security security vulnerability
In Avast Premium Security 19.8.2393, attackers can send a specially crafted request to the local web server run by Avast Antivirus on port 27275 to support Bank Mode functionality. A flaw in the processing of a command allows execution of arbitrary OS commands with the privileges of the currently logged in user. This allows for example attackers who compromised a browser extension to escape from the browser sandbox.
- Severity
- High
- CVSS
- 9.3 (2.0)
- Published
- 2020-01-13
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-78
Affected products
- avast / premium_security / 19.8.2393
Matched remediation archetype
Command, code, expression, and template injection
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Check exposure
- Trace untrusted values to process execution, interpreters, evaluators, template engines, dynamic imports, and administrative scripting features.
- Determine whether the affected path is reachable across each trust boundary and which service account or host privilege it inherits.
- Review configuration for optional execution features, unsafe compatibility modes, and shell invocation.
Remediate safely
- Replace string-built commands or evaluated code with fixed operations and structured argument APIs that do not invoke a shell.
- Use strict allowlists for operation identifiers and reject unexpected input before it reaches any interpreter.
- Update the affected component and add inert regression tests covering metacharacters, encoding variants, and alternate request paths.
Authoritative sources
Complete CVE record and remediation plan
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