CVE-2026-20045
Cisco Unified Communications Products Code Injection Vulnerability
Cisco Unified Communications Manager
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.
Ransomware groups exploiting CVE-2026-20045
ShinyHunters is a financially motivated data-theft and extortion group active since 2020, responsible for high-profile breaches including Ticketmaster (via Snowflake) and PowerSchool; by 2025 they launched a RaaS offering called "shinysp1d3r," and in August 20
Exploitation is attributed to these groups across their recorded activity. It does not follow that every organisation they listed was reached through CVE-2026-20045 — the source data does not record an entry point per incident.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 21 January 2026. US federal agencies were required to remediate it by 11 February 2026.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 4.3%, which is higher than 90.2% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Recent listings by these groups
Disclosures from the groups above, newest first.
Frequently asked questions
Is CVE-2026-20045 being exploited by ransomware groups?
Yes. CVE-2026-20045 is recorded as exploited by Shinyhunters. Between them these groups account for 139 victim disclosures in this database.
What does CVE-2026-20045 affect?
CVE-2026-20045 affects Cisco Unified Communications Manager. 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.
How severe is CVE-2026-20045?
CVE-2026-20045 is rated HIGH with a CVSS base score of 8.2. EPSS puts the probability of exploitation in the next 30 days at 4.3%, higher than 90.2% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 11 February 2026.
How should organisations respond to CVE-2026-20045?
Apply the vendor patch for Cisco Unified Communications Manager as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.