CVE intelligence and bounded remediation
CVE-2018-18555 — A sandbox escape issue was discovered in VyOS 1.1.8
A sandbox escape issue was discovered in VyOS 1.1.8. It provides a restricted management shell for operator users to administer the device. By issuing various shell special characters with certain commands, an authenticated operator user can break out of the management shell and gain access to the underlying Linux shell. The user can then run arbitrary operating system commands with the privileges afforded by their account.
- Severity
- Critical
- CVSS
- 9.9 (3.0)
- Published
- 2018-12-17
- CISA KEV
- Not currently listed
- Ecosystem
- operating-system
- Weaknesses
- CWE-78
Affected products
- vyos / vyos / 1.1.8
Matched remediation archetype
Command, code, expression, and template injection
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
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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