Patchfirst
CVE-2026-20045 KEVPublic exploit Critical · 9.8 EPSS 4.5%

Cisco Unified Communications Products Code Injection Vulnerability

Cisco · Unified Communications Manager

Summary

Cisco Unified Communications Manager, its SME and IM&P variants, Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance contain an improper input validation flaw in the handling of user-supplied data in HTTP requests to the web-based management interface. An unauthenticated remote attacker can exploit it by sending a sequence of crafted HTTP requests to that interface, without user interaction, to run arbitrary commands on the underlying operating system and then escalate privileges to root.

Official description · NVD

A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P), Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance could allow an unauthenticated, remote attacker to execute arbitrary commands on the underlying operating system of an affected device.  This vulnerability is due to improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by sending a sequence of crafted HTTP requests to the web-based management interface of an affected device. A successful exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root.  Note: Cisco has assigned this security advisory a Security Impact Rating (SIR) of Critical rather than High as the score indicates. The reason is that exploitation of this vulnerability could result in an attacker elevating privileges to root.

Breakdown
73.2 / 100
Exploited
Yes, in CISA KEV
Reports
0
Tactics
2/15

How an attack unfolds

Based on mappings. Select a step to see the evidence.
  1. How attackers get in

  2. What they do

First seen exploited the day it was disclosed. Public exploit code (PoC-in-GitHub) appeared 4 days after disclosure.

  1. DisclosedFirst seen exploitedVulnCheck KEV evidenceAdded to CISA KEVEU database agreesday 0
  2. Public exploit codePoC-in-GitHub+4 days

CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.

techniques

2 , grouped by in kill-chain order, 2 cited passages 2

Initial AccessTA0001

Exploit Public-Facing Application T1190 Medium
AI mapping from the description · how it is exploited

unauthenticated remote exploit of web management interface

could allow an unauthenticated, remote attacker to execute arbitrary commands
From the official description (NVD) Original (opens in a new tab) ↗

ExecutionTA0002

Command and Scripting Interpreter T1059 Medium
AI mapping from the description · primary impact

arbitrary OS command execution after exploitation

execute arbitrary commands on the underlying operating system
From the official description (NVD) Original (opens in a new tab) ↗

Detection

0 rules for this CVE · 244 general rules for its techniques

Rules for this CVE

0 that reference CVE-2026-20045 directly.

CVE-specific rules are not available in this build. Search SigmaHQ ↗

Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.

What security researchers reported

Not named in any threat report yet

Also mentioned in 50 community threat pulses (AlienVault OTX)

Weaker evidence

Pulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.

References

2 links, grouped by NVD tag
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