Cisco UCS Manager Software SSH Sessions Denial of Service Vulnerability
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-770.
Summary
A vulnerability in the way Cisco UCS Manager software handles SSH sessions could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper resource management for established SSH sessions. An attacker could exploit this vulnerability by opening a significant number of SSH sessions on an affected device. A successful exploit could allow the attacker to cause a crash and restart of internal Cisco UCS Manager software processes and a temporary loss of access to the Cisco UCS Manager CLI and web UI. Note: The attacker must have valid user credentials to authenticate to the affected device.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Cisco | Cisco Unified Computing System (Managed) | all versions | — | No fix listed | CNA |
- Cisco Unified Computing System (Managed) VendorCisco Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 3
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:cisco:unified_computing_system:*:*:*:*:*:*:*:* | 4.0 to before 4.0\(4m\); 4.1 to before 4.1\(3e\) | Vulnerable | Cisco |
| cpe:2.3:h:cisco:unified_computing_system_64108:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Cisco |
| cpe:2.3:h:cisco:unified_computing_system_6454:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Cisco |
- cpe:2.3:a:cisco:unified_computing_system:*:*:*:*:*:*:*:* Versions 4.0 to before 4.0\(4m\); 4.1 to before 4.1\(3e\) Vulnerable ·Cisco
- cpe:2.3:h:cisco:unified_computing_system_64108:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
- cpe:2.3:h:cisco:unified_computing_system_6454:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2021-1592
- 2026-10-03 Alias added: GHSA-g536-3jmm-mp33
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- TI-2020-08191 IP-in-IP protocol allows a remote, unauthenticated attacker to route arbitrary network traffic CVSS 3.1MEDIUM 5.3
- TI-2018-00390 Cisco Integrated Management Controller Command Injection Vulnerability CVSS 3.0HIGH 8.8
- TI-2018-00389 Cisco Integrated Management Controller Command Injection Vulnerability CVSS 3.0HIGH 8.8
- TI-2021-01114 Cisco NX-OS Software IPv6 Netstack Denial of Service Vulnerability CVSS 3.1HIGH 8.6
Sources
- CVE-2021-1592 · CVE Program
- CVE-2021-1592 · NVD
- FIRST EPSS
- GHSA-g536-3jmm-mp33 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences