Multiple Cisco Products Server Name Identification Data Exfiltration Vulnerability
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-200.
Summary
A vulnerability in Server Name Identification (SNI) request filtering of Cisco Web Security Appliance (WSA), Cisco Firepower Threat Defense (FTD), and the Snort detection engine could allow an unauthenticated, remote attacker to bypass filtering technology on an affected device and exfiltrate data from a compromised host. This vulnerability is due to inadequate filtering of the SSL handshake. An attacker could exploit this vulnerability by using data from the SSL client hello packet to communicate with an external server. A successful exploit could allow the attacker to execute a command-and-control attack on a compromised host and perform additional data exfiltration attacks.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- 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 Web Security Appliance (WSA) | all versions | — | No fix listed | CNA |
- Cisco Web Security Appliance (WSA) VendorCisco Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:cisco:ironport_web_security_appliance:14.5:*:*:*:*:*:*:* | 14.5 | Vulnerable | Cisco |
| cpe:2.3:a:cisco:secure_firewall_management_center:2.9.18:*:*:*:*:*:*:* | 2.9.18 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:firepower_management_center_virtual_appliance_firmware:6.6.0:*:*:*:*:*:*:* | 6.6.0 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:firepower_management_center_virtual_appliance_firmware:6.7.0:*:*:*:*:*:*:* | 6.7.0 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:firepower_management_center_virtual_appliance_firmware:7.0.0:*:*:*:*:*:*:* | 7.0.0 | Vulnerable | Cisco |
| cpe:2.3:o:cisco:firepower_management_center_virtual_appliance_firmware:7.1.0:*:*:*:*:*:*:* | 7.1.0 | Vulnerable | Cisco |
- cpe:2.3:a:cisco:ironport_web_security_appliance:14.5:*:*:*:*:*:*:* Versions 14.5 Vulnerable ·Cisco
- cpe:2.3:a:cisco:secure_firewall_management_center:2.9.18:*:*:*:*:*:*:* Versions 2.9.18 Vulnerable ·Cisco
- cpe:2.3:o:cisco:firepower_management_center_virtual_appliance_firmware:6.6.0:*:*:*:*:*:*:* Versions 6.6.0 Vulnerable ·Cisco
- cpe:2.3:o:cisco:firepower_management_center_virtual_appliance_firmware:6.7.0:*:*:*:*:*:*:* Versions 6.7.0 Vulnerable ·Cisco
- cpe:2.3:o:cisco:firepower_management_center_virtual_appliance_firmware:7.0.0:*:*:*:*:*:*:* Versions 7.0.0 Vulnerable ·Cisco
- cpe:2.3:o:cisco:firepower_management_center_virtual_appliance_firmware:7.1.0:*:*:*:*:*:*:* Versions 7.1.0 Vulnerable ·Cisco
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2021-34749
- 2026-10-03 Alias added: GHSA-x64m-mg53-f49j
References
More Cisco Firepower Management Center Virtual Appliance Firmware vulnerabilities
- TI-2019-11380 Cisco Firepower Management Center Multiple Cross-Site Scripting Vulnerabilities CVSS 3.1MEDIUM 4.8
- TI-2019-11381 Cisco Firepower Management Center Multiple Cross-Site Scripting Vulnerabilities CVSS 3.1MEDIUM 4.8
Sources
- CVE-2021-34749 · CVE Program
- CVE-2021-34749 · NVD
- FIRST EPSS
- GHSA-x64m-mg53-f49j · 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