Cisco Unified Communications Products Code Injection
CVE-2026-20045 is a critical-severity improper control of generation of code vulnerability in Cisco Unified Communications Manager from Cisco, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Cisco Unified Communications Manager versions: 12.5(1)SU2; 12.5(1)SU1; 12.5(1), and others listed below. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on January 21, 2026, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Unified Communications Manager to 14su5 or a later version.
- Update Unified Communications Manager Im And Presence Service to 14su5 or a later version.
- Update Unity Connection to 14su5 or a later version.
- CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco Unified Communications Manager | 12.5(1)SU2; 12.5(1)SU1; 12.5(1); 12.5(1)SU3; 12.5(1)SU4; 14; 12.5(1)SU5; 14SU1; and 23 more ranges | Not stated |
| Cisco | Cisco Unified Communications Manager IM and Presence Service | 12.5(1); 12.5(1)SU1; 12.5(1)SU2; 12.5(1)SU3; 12.5(1)SU4; 14; 12.5(1)SU5; 14SU1; and 12 more ranges | Not stated |
| Cisco | Cisco Unity Connection | 12.5(1); 12.5(1)SU1; 12.5(1)SU2; 12.5(1)SU3; 12.5(1)SU4; 14; 12.5(1)SU5; 14SU1; and 13 more ranges | Not stated |
| Cisco | Unified Communications Manager | 12.5 up to, but not including, 14su5; 15.0 through 15su3a | 14su5 |
| Cisco | Unified Communications Manager Im And Presence Service | 12.5 up to, but not including, 14su5; 15.0 through 15su3a | 14su5 |
| Cisco | Unity Connection | 12.5 up to, but not including, 14su5; 15.0 through 15su3 | 14su5 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.2 | High | CNA (cisco.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Control of Generation of Code
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
How developers prevent this class of flaw
- Refactor your program so that you do not have to dynamically generate code.
- Run your code in a jail or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.
More Improper Control of Generation of Code vulnerabilities (CWE-94)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20045US Government Resource
Other vulnerabilities in Cisco Unified Communications Manager
- 7.5 High severity
- 7.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 9.3 Critical severity
Recent Improper Control of Generation of Code vulnerabilities
- 9.8 Critical severity
- 9.6 Critical severity
- 9.8 Critical severity
- 7.8 High severity
- 9.8 Critical severity
- 9.9 Critical severity
Spotted an error? Tell us.