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PatchSiren cyber security CVE debrief

CVE-2020-3161 Cisco CVE debrief

CVE-2020-3161 affects Cisco IP Phones web server functionality and is described as a remote code execution and denial-of-service vulnerability. It was added to CISA’s Known Exploited Vulnerabilities catalog on 2021-11-03, which means defenders should treat it as actively exploited risk and prioritize vendor-guided patching and mitigation.

Vendor
Cisco
Product
Cisco IP Phones
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2021-11-03
Original CVE updated
2021-11-03
Advisory published
2021-11-03
Advisory updated
2021-11-03

Who should care

Organizations that use Cisco IP Phones, especially teams responsible for voice infrastructure, endpoint/telephony management, and network security operations, should prioritize this CVE. It is also relevant to asset owners who may not manage phones directly but rely on centralized Cisco voice deployments.

Technical summary

The available official metadata identifies the issue as a Cisco IP Phones web server vulnerability with potential remote code execution and denial-of-service impact. CISA’s KEV entry confirms the vulnerability is known to be exploited and directs operators to apply updates per vendor instructions. No additional technical details were included in the supplied corpus, so analysis should remain limited to the official classification and remediation guidance.

Defensive priority

High

Recommended defensive actions

  • Identify all Cisco IP Phones models and deployments in scope.
  • Check Cisco's official guidance for affected versions and required updates.
  • Apply vendor-recommended updates or mitigations as soon as practical.
  • Prioritize internet-exposed or broadly reachable phone management interfaces.
  • Verify remediation by confirming updated firmware/software versions across the fleet.
  • Track this CVE as a known-exploited item in vulnerability management workflows.

Evidence notes

Evidence is limited to official metadata from CISA KEV and linked official records. The CISA KEV source identifies the vulnerability name, affected product family (Cisco IP Phones), date added (2021-11-03), and required action ('Apply updates per vendor instructions.'). The supplied corpus does not include Cisco advisory text, CVSS scoring, affected version ranges, or exploitation details beyond KEV inclusion.

Official resources

Publicly disclosed; added to CISA’s Known Exploited Vulnerabilities catalog on 2021-11-03. This debrief relies only on official records and metadata supplied in the corpus.