CVE-2020-3161: Cisco IP Phones Web Server Remote Code Execution and Denial-of-Service Vulnerability
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
Cisco IP Phones contain an improper input validation vulnerability for HTTP requests. Exploitation could allow an attacker to execute code remotely with root privileges or cause a denial-of-service (DoS) condition.
CSIRTS triage
- What
- An improper input validation vulnerability could allow remote code execution or denial-of-service conditions.
- Who is affected
- Deployments of Cisco IP Phones are affected.
- Urgency
- Remediation is urgent as the vulnerability is actively exploited and critical.
- Action
- Update to the latest firmware for Cisco IP Phones.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2020-3161
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Exploitation confirmedCVE-2020-3161Already exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 99.7% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2020-3161 | coverage & exploitation status | NVD · CVE.org |
Recent advisories for Cisco IP Phones
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- medium[NEW] [medium] Cisco IP Phone: Vulnerability enables Denial of Servicecert-bund · 2026-09-03
- highCVE-2026-20281: A vulnerability in Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisc…nvd · 2026-09-02
- highCisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Denial of …cisco-psirt · 2026-09-02
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