Cisco Catalyst SD-WAN Manager Improper Encoding or Escaping of Output
CVE-2026-20245 is a high-severity improper encoding or escaping of output vulnerability in Cisco Catalyst SD-WAN Controller from Cisco, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. Affected Cisco Catalyst SD-WAN Controller versions: 20.6.4; 20.9.2; 20.3.6, 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 June 9, 2026, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Catalyst Sd-wan Manager to 20.9.9.1 or 20.12.5.4 or 20.12.6.2 or 20.15.4.4, whichever matches your release line, or a later version.
- Update Sd-wan Vsmart Controller to 20.9.9.1 or 20.12.5.4 or 20.12.6.2 or 20.15.4.4, whichever matches your release line, 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.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco Catalyst SD-WAN Controller | 20.6.4; 20.9.2; 20.3.6; 20.7.2; 20.7.1; 20.5.1; 20.6.2; 19.3.0; and 32 more ranges | Not stated |
| Cisco | Cisco Catalyst SD-WAN Manager | 20.1.12; 19.2.1; 18.4.4; 18.4.5; 20.1.1.1; 20.1.1; 19.3.0; 19.2.2; and 32 more ranges | Not stated |
| Cisco | Catalyst Sd-wan Manager | before 20.9.9.1; 20.10 up to, but not including, 20.12.5.4; 20.12.6 up to, but not including, 20.12.6.2; 20.13 up to, but not including, 20.15.4.4; 20.15.5 up to, but not including, 20.15.5.2; 20.16 up to, but not including, 20.18.2.2; 26.1 up to, but not including, 26.1.1.1; 20.12.7 | 20.9.9.1, 20.12.5.4, 20.12.6.2, 20.15.4.4, 20.15.5.2, 20.18.2.2 |
| Cisco | Sd-wan Vsmart Controller | before 20.9.9.1; 20.10 up to, but not including, 20.12.5.4; 20.12.6 up to, but not including, 20.12.6.2; 20.13 up to, but not including, 20.15.4.4; 20.15.5 up to, but not including, 20.15.5.2; 20.16 up to, but not including, 20.18.2.2; 26.1 up to, but not including, 26.1.1.1; 20.12.7 | 20.9.9.1, 20.12.5.4, 20.12.6.2, 20.15.4.4, 20.15.5.2, 20.18.2.2 |
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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- 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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (cisco.com).
Official description
A vulnerability in the CLI of Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, and Cisco Catalyst SD-WAN Validator, formerly SD-WAN vBond, could allow an authenticated, local attacker to execute arbitrary commands as root by supplying a crafted file to the affected system. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by uploading a crafted file to the affected system. A successful exploit could allow the attacker to perform command injection attacks on an affected system and elevate their privileges as the root user. To exploit this vulnerability, the attacker must have netadmin privileges on the affected system. This would require valid credentials or exploitation of or . Cisco is not aware of successful exploitation by other methods. Cisco has observed limited cases where the exploitation of this bug resulted in a configuration change pushed to edge devices. Cisco recommends that customers upgrade to the fixed software that is documented in the that was published on May 14, 2026, and verify the configuration of the edge devices.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Encoding or Escaping of Output
The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.
How developers prevent this class of flaw
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using the ESAPI Encoding control or a similar tool, library, or framework. These will help the programmer encode outputs in a manner less prone to error. Alternately, use built-in functions, but consider using wrappers in case those functions are discovered to have a vulnerability.
- If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated. For example, stored procedures can enforce database query structure and reduce the likelihood of SQL injection.
- Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages. Study all expected communication protocols and data representations to determine the required encoding strategies.
More Improper Encoding or Escaping of Output vulnerabilities (CWE-116)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- 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-2026-20245US Government Resource
Other vulnerabilities in Cisco Catalyst SD-WAN Controller
- 7.7 High severity
- 8.8 High severity
- 9.1 Critical severity
- 9.9 Critical severity
- 9.9 Critical severity
- 10.0 Critical severity
Recent Improper Encoding or Escaping of Output vulnerabilities
- 9.6 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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