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Vulnerabilities

CriticalKEV

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

CVE-2020-3161 · Cisco IP phone · CVSS 9.8 · KEV

In brief

Severity · CVSS
Critical9.8CVSS 3.1, Critical
EPSS
84%
CISA KEV
Known exploited, listed since 3 Nov 2021
CERT-FR
No advisory or alert referenced in the catalog
Vendor
Cisco
Published · Modified
·
Last verified

Summary

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.

Weakness: CWE-20

Title, description and the vendor's statements are quoted from the CVE record; a vendor's advisory is summarised in Patcharo's words, with a link.

Affected and fixed versions

Per product and release branch, as the vendor's CVE record and official advisory state them. A fixed release is shown only when a document names it: the vendor's, or CERT-FR's for Check Point, with its source.

Cisco IP phone

Source: CVE-2020-3161cisco-sa-voip-phones-rce-dos-rB6EeRXs

  1. —
    Affected versionsn/a
    First fixed releaseNot published in the sources followed

The vendor states fixes are available; the releases per branch are in its advisory.

Remediation

Fix available

Vendor fix

Cisco has released updates that fix this vulnerability; its advisory lists them.

SourceCisco Security Advisory cisco-sa-voip-phones-rce-dos-rB6EeRXs· revised 16 Apr 2020

Mitigation (vendor)

Cisco describes a workaround or a mitigation in its advisory.

SourceCisco Security Advisory cisco-sa-voip-phones-rce-dos-rB6EeRXs

CISA KEV required action

Apply updates per vendor instructions.

CISA due date:

SourceCISA KEV

Last verified 1 Oct 2026 at 09:30 UTC

Known exploitation

Added to CISA KEV on 3 Nov 2021

Federal remediation due date: 3 May 2022

The CISA required action is shown under Remediation.

84% probability of exploitation in the next 30 days (percentile 100%).

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CERT-FR

No CERT-FR advisory or alert of the last two years references this CVE, for the vendors Patcharo covers.

Timeline

  1. Published by the source
  2. Added to CISA KEV
  3. CISA remediation due date
  4. Source record last modified
  5. EPSS score computed
  6. Last verified by Patcharo

Official sources

Vendor advisory

References

Cisco · CISA Known Exploited Vulnerabilities · NVD · FIRST EPSS · Cisco Security Advisory cisco-sa-voip-phones-rce-dos-rB6EeRXs

How Patcharo reads this

Affected and fixed releases come from the vendor's structured statements and are matched against exact versions; CVSS from NVD, exploitation from CISA KEV and the vendor's own advisory, probability from FIRST EPSS. Missing data stays Unknown and never becomes Not affected.

Read the methodologyRead the guide: Cisco Secure Firewall release trains: Threat Defense, Management Center and ASA versions explained