CVE intelligence and bounded remediation

CVE-2021-1602 — Cisco Small Business Rv Series Router Firmware security vulnerability

Critical CVSS 9.8

A vulnerability in the web-based management interface of Cisco Small Business RV160, RV160W, RV260, RV260P, and RV260W VPN Routers could allow an unauthenticated, remote attacker to execute arbitrary commands on the underlying operating system of an affected device. This vulnerability is due to insufficient user input validation. An attacker could exploit this vulnerability by sending a crafted request to the web-based management interface. A successful exploit could allow the attacker to execute arbitrary commands on an affected device using root-level privileges. Due to the nature of the vulnerability, only commands without parameters can be executed.

Severity
Critical
CVSS
9.8 (3.1)
Published
2021-08-04
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-78, CWE-20

Affected products

  • cisco / small_business_rv_series_router_firmware

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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