Threats / Cisco / CVE-2020-3161
CVE-2020-3161
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Cisco IP Phones vulnerability
Cisco IP Phones contain an improper input validation vulnerability in HTTP request handling that could allow remote code execution with root privileges or denial-of-service attacks.
Verdict
Today item — known-exploited.
An unauthenticated attacker can exploit improper input validation in Cisco IP Phones to execute arbitrary code with root-level privileges or disrupt phone availability. The high EPSS score and active exploitation in the wild indicate immediate risk.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
1 independent public report of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03).
Probability (EPSS)
EPSS 0.83734 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Cisco, Cisco IP Phones. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-20 Improper Input Validation.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious HTTP request with invalid input that bypasses validation checks on the target IP phone.
Business
Attackers gain a foothold in enterprise telephony infrastructure, potentially compromising call security and data.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I execute arbitrary code with root privileges on the compromised phone to establish persistence or pivot to the network.
Business
The organization faces lateral movement risk, credential theft, and potential compromise of connected systems and sensitive communications.
3
Lateral reach — past segmentation narrative 3
Attacker
I alternatively send crafted requests to trigger a denial-of-service condition, rendering phones inoperable.
Business
Business continuity is disrupted as employees lose access to critical voice communications, impacting operations and customer service.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05