Skip to content
Weekly Signal
Live intelligence Updated 20 Aug 2026 · 12:21 UTC

Cisco · 8831 Firmware, Cisco IP Phones, Ip Phone 7811 Firmware +11 more

CVE-2020-3161

Cisco IP Phones Web Server Remote Code Execution and Denial-of-Service Vulnerability

Recommended action

Validate affected assets and exposure now, then remediate on an accelerated schedule. Cisco Security advisory Cisco Sa Voip Phones Rce Dos RB6EeRXs

View response plan
CVSS9.8
EPSS83.7%
KEVYes
ExploitationConfirmed exploitation
RemediationNot yet verified ↓

Assessment

Why it matters

CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 83.7%; technical severity is CVSS 9.8.

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.

Who should care

  • Teams operating 8831 Firmware, Cisco IP Phones, Ip Phone 7811 Firmware +11 more
  • Vulnerability and exposure management teams
  • Security operations teams monitoring exploitation activity

Response plan

What I would do

  1. Confirm whether 8831 Firmware, Cisco IP Phones, Ip Phone 7811 Firmware +11 more is present in the environment.
  2. Identify affected versions and establish whether vulnerable services are exposed or reachable.
  3. Cisco Security advisory Cisco Sa Voip Phones Rce Dos RB6EeRXs
  4. Review relevant security telemetry for evidence of attempted or successful exploitation.
  5. Document the remediation decision and track it to verified completion.

Treatment intelligence

Remediation intelligence

Not yet verified

Vendor sources are listed before government and third-party guidance. Confirm product applicability and change prerequisites before deployment.

Verification noteAutomated link verification has not completed for this guidance yet.

Technical details

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-20
Affected versions
Cisco 8831 Firmware (Version 10.3(1)es14 | Version 11.0(1) | Version 11.0(5)sr1); Cisco Cisco IP Phones; Cisco Ip Phone 7811 Firmware (Version 11.0(1)); Cisco Ip Phone 7821 Firmware (Version 11.0(1)); Cisco Ip Phone 7841 Firmware (Version 11.0(1)); Cisco Ip Phone 7861 Firmware (Version 11.0(1)); Cisco Ip Phone 8811 Firmware (Version 10.3(1)es14 | Version 11.0(1) | Version 11.0(5)sr1); Cisco Ip Phone 8821 Firmware (Version 10.3(1)es14 | Version 11.0(1) | Version 11.0(5)sr1)
Fixed versions
No explicit fixed version is currently recorded.
Published
15 April 2020
Attack vector
Network
Privileges required
None
User interaction
None

Signal timeline

  1. CVE published
  2. Added to CISA KEV
  3. Latest EPSS score: 83.7%
  4. Signal calculated at 83

External references

Live public intelligence This assessment combines public-source evidence. Validate the affected product, version and exposure against your own environment before making a risk decision.