What’s Vulnerable › Vulnerabilities

CVE-2020-3244: Cisco ASR 5000 Series Aggregation Services Routers Enhanced Charging Service Rule Bypass Vulnerability

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-06-18 · updated 2026-06-17
• Weakness: CWE-20

Description

A vulnerability in the Enhanced Charging Service (ECS) functionality of Cisco ASR 5000 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass the traffic classification rules on an affected device. The vulnerability is due to insufficient input validation of user traffic going through an affected device. An attacker could exploit this vulnerability by sending a malformed HTTP request to an affected device. A successful exploit could allow the attacker to bypass the traffic classification rules and potentially avoid being charged for traffic consumption.

Affected products

• Cisco StarOS: before 21.18.0 — fixed in 21.18.0

How to fix

Upgrade to a fixed version: Cisco StarOS 21.18.0. Check the vendor advisory for mitigations.

References

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asr5k-ecs-bypass-2LqfPCL
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asr5k-ecs-bypass-2LqfPCL

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