CVE intelligence and bounded remediation

CVE-2020-3161 — Cisco IP Phones Web Server Remote Code Execution and Denial-of-Service Vulnerability

Critical CVSS 9.8 CISA KEV

A vulnerability in the web server for Cisco IP Phones could allow an unauthenticated, remote attacker to execute code with root privileges or cause a reload of an affected IP phone, resulting in a denial of service (DoS) condition. The vulnerability is due to a lack of proper input validation of HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the web server of a targeted device. A successful exploit could allow the attacker to remotely execute code with root privileges or cause a reload of an affected IP phone, resulting in a DoS condition.

Severity
Critical
CVSS
9.8 (3.1)
Published
2020-04-15
CISA KEV
Known exploited
Ecosystem
operating-system
Weaknesses
CWE-20

Affected products

  • cisco / ip_phone_8865_firmware / 10.3(1)es14
  • cisco / ip_phone_8865_firmware / 11.0(1)
  • cisco / ip_phone_8865_firmware / 11.0(5)sr1
  • cisco / ip_phone_8851_firmware / 10.3(1)es14
  • cisco / ip_phone_8851_firmware / 11.0(1)
  • cisco / ip_phone_8851_firmware / 11.0(5)sr1

Showing 6 representative product identities from 31 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Resource exhaustion and denial of service

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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