CVE-2026-20188

Cisco Crosswork Network Controller and Cisco Network Services Orchestrator Advisory

Published May 6, 2026 CVSS 3.1 · 0 Low EPSS < 1% KEV · Not listed

Description

Following the initial publication of the Security Advisory about a denial of service (DoS) condition in Cisco Crosswork Network Controller and Cisco Network Services Orchestrator (NSO), additional information has been made available to the Cisco Product Security Incident Response Team (PSIRT).

Upon further analysis, the Cisco PSIRT has reclassified this issue as a customer-configurable, resource management issue rather than a security vulnerability.

Analysis

Technical impact

A flaw in the connection‑handling mechanism of Cisco Crosswork Network Controller and Cisco Network Services Orchestrator allows an attacker who does not need to be authenticated to flood the system with a large number of connection requests. The inadequate rate limiting causes the service to consume all available connection resources, rendering the controller or orchestrator unresponsive. The resulting denial of service requires a manual reboot to restore normal operation. This vulnerability directly affects the availability of the affected services.

Affected Systems

Cisco Crosswork Network Change Automation and Cisco Network Services Orchestrator are impacted. Specific version information is not supplied in the advisory.

Risk and Exploitability

The CVSS score is not available, leaving the severity assessment uncertain. EPSS score of 0.0014 (less than 1%) indicates a very low probability of exploitation. The vulnerability is not listed in CISA's KEV catalog. Because the attack requires only unauthenticated remote access and relies on sending many connections, an attacker with network reach to the affected system can exploit it using readily available tools, and escalation of privileges is not required.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor	Product	Default status	Versions
Cisco	Cisco Crosswork Network Change Automation	unaffected	—

No data.

Vendor Product Versions

Cisco

Crosswork Network Automation

Version	Status	Scheme	Platform
`3.0.0`	affected	semver	—
`1.0.0`	affected	semver	—
`2.0.2`	affected	semver	—
`4.0.0`	affected	semver	—
`4.1.0`	affected	semver	—
`4.5.0`	affected	semver	—
`5.0.0`	affected	semver	—
`4.5.1`	affected	semver	—
`4.5.2`	affected	semver	—
`5.0.2`	affected	semver	—
`4.1.3`	affected	semver	—
`6.0.0`	affected	semver	—
`7.0.0`	affected	semver	—
`4.1.4`	affected	semver	—
`5.0.4`	affected	semver	—
`7.1.0`	affected	semver	—
`7.0.3`	affected	semver	—
`7.1.3`	affected	semver	—

Cisco

Network Services Orchestrator

Version	Status	Scheme	Platform
`5.7`	affected	semver	—
`5.7.1`	affected	semver	—
`5.7.1.1`	affected	semver	—
`5.7.2`	affected	semver	—
`5.7.2.1`	affected	semver	—
`5.7.3`	affected	semver	—
`5.8`	affected	semver	—
`5.6.6.1`	affected	semver	—
`5.7.5.1`	affected	semver	—
`5.6.7.1`	affected	semver	—
`5.6.7`	affected	semver	—
`5.8.1`	affected	semver	—
`5.6.6`	affected	semver	—
`5.8.2.1`	affected	semver	—
`5.7.5`	affected	semver	—
`5.7.4`	affected	semver	—
`5.8.2`	affected	semver	—
`5.6.7.2`	affected	semver	—
`5.7.6`	affected	semver	—
`5.7.6.1`	affected	semver	—
`5.8.3`	affected	semver	—
`5.6.8`	affected	semver	—
`5.7.6.2`	affected	semver	—
`5.8.4`	affected	semver	—
`5.7.7`	affected	semver	—
`5.6.9`	affected	semver	—
`5.6.8.1`	affected	semver	—
`5.8.5`	affected	semver	—
`5.7.8`	affected	semver	—
`5.6.10`	affected	semver	—
`5.8.6`	affected	semver	—
`6.0`	affected	semver	—
`5.7.8.1`	affected	semver	—
`6.0.1`	affected	semver	—
`5.6.11`	affected	semver	—
`5.8.7`	affected	semver	—
`6.0.2`	affected	semver	—
`5.7.9`	affected	semver	—
`5.6.12`	affected	semver	—
`5.8.8`	affected	semver	—
`6.0.3`	affected	semver	—
`5.7.10`	affected	semver	—
`5.6.13`	affected	semver	—
`5.8.9`	affected	semver	—
`6.0.4`	affected	semver	—
`5.7.10.1`	affected	semver	—
`6.1`	affected	semver	—
`5.7.6.3`	affected	semver	—
`5.7.11`	affected	semver	—
`6.0.5`	affected	semver	—
`5.6.14`	affected	semver	—
`5.8.10`	affected	semver	—
`6.0.6`	affected	semver	—
`5.7.12`	affected	semver	—
`5.6.14`	affected	semver	—
`5.8.10`	affected	semver	—
`6.0.7`	affected	semver	—
`5.7.13`	affected	semver	—
`5.8.11`	affected	semver	—
`6.0.8`	affected	semver	—
`5.6.14.1`	affected	semver	—
`5.8.12`	affected	semver	—
`6.0.9`	affected	semver	—
`5.8.13`	affected	semver	—
`5.7.14`	affected	semver	—
`6.0.10`	affected	semver	—
`6.0.11`	affected	semver	—
`5.7.15`	affected	semver	—
`6.0.12`	affected	semver	—
`5.7.9.1`	affected	semver	—
`5.7.15.1`	affected	semver	—
`6.0.13`	affected	semver	—
`5.6.14.3`	affected	semver	—
`5.8.13.1`	affected	semver	—
`5.7.16`	affected	semver	—
`5.7.17`	affected	semver	—
`5.7.17.1`	affected	semver	—
`5.7.18`	affected	semver	—
`5.7.19`	affected	semver	—
`5.7.19.1`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply any Cisco Crosswork Network Change Automation or Cisco Network Services Orchestrator patch that addresses the rate‑limiting issue as soon as it becomes available.
If a patch is not yet available, enforce network‑level rate limiting or firewall rules to restrict the number of inbound connection attempts to the affected services.
Continuously monitor system logs for excessive connection attempts and investigate anomalous traffic patterns to identify attempted exploitation.

Generated by OpenCVE AI on May 14, 2026 at 19:05 UTC.

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.310% probability within 30 days)

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nso-dos-7Egqyc

History

May 14, 2026 5:00 PM Description updated. Title updated. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description	A vulnerability in the connection-handling mechanism of Cisco Crosswork Network Controller (CNC) and Cisco Network Services Orchestrator (NSO) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected system. This vulnerability is due to an inadequate implementation of rate-limiting on incoming network connections. An attacker could exploit this vulnerability by sending a large number of connection requests to an affected system. A successful exploit could allow the attacker to exhaust available connection resources, causing Cisco CNC and Cisco NSO to become unresponsive and resulting in a DoS condition for legitimate users and dependent services. A manual reboot of the system is required to recover from this condition.	Following the initial publication of the Security Advisory about a denial of service (DoS) condition in Cisco Crosswork Network Controller and Cisco Network Services Orchestrator (NSO), additional information has been made available to the Cisco Product Security Incident Response Team (PSIRT). Upon further analysis, the Cisco PSIRT has reclassified this issue as a customer-configurable, resource management issue rather than a security vulnerability.
Title	Cisco Crosswork Network Controller and Cisco Network Services Orchestrator Connection Exhaustion Denial of Service Vulnerability	Cisco Crosswork Network Controller and Cisco Network Services Orchestrator Advisory
Metrics	cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}`	cvssV3_1 `{'score': 0, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N'}`

May 7, 2026 8:30 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Cisco Cisco crosswork Network Automation Cisco network Services Orchestrator
Vendors & Products		Cisco Cisco crosswork Network Automation Cisco network Services Orchestrator

May 6, 2026 6:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

May 6, 2026 4:45 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		A vulnerability in the connection-handling mechanism of Cisco Crosswork Network Controller (CNC) and Cisco Network Services Orchestrator (NSO) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected system. This vulnerability is due to an inadequate implementation of rate-limiting on incoming network connections. An attacker could exploit this vulnerability by sending a large number of connection requests to an affected system. A successful exploit could allow the attacker to exhaust available connection resources, causing Cisco CNC and Cisco NSO to become unresponsive and resulting in a DoS condition for legitimate users and dependent services. A manual reboot of the system is required to recover from this condition.
Title		Cisco Crosswork Network Controller and Cisco Network Services Orchestrator Connection Exhaustion Denial of Service Vulnerability
Weaknesses		CWE-400
References		https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nso-dos-7Egqyc
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}`