CVE-2022-20960
A vulnerability in Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of certain TLS connections that are processed by an affected device. An attacker could exploit this vulnerability by establishing a large number of concurrent TLS connections to an affected device. A successful exploit could allow the attacker to cause the device to drop new TLS email messages that come from the associated email servers. Exploitation of this vulnerability does not cause the affected device to unexpectedly reload. The device will recover autonomously within a few hours of when the attack is halted or mitigated.
Key facts
- CVSS score
- 7.5 (v3.1)
- Severity
- HIGH
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
- CWE-400
- EPSS score
- 0.8% (57th percentile)
- In CISA KEV
- No
- In EU EUVD
- Yes (EUVD-2022-26210)
- Published
- November 4, 2022
- NVD last modified
- June 17, 2026
- Status
- Modified
EU Vulnerability Database (EUVD)
This vulnerability is also tracked by ENISA as EUVD-2022-26210 in the EU Vulnerability Database. Last updated in EUVD on August 3, 2024.
View on the EU Vulnerability DatabaseAffected products
- cisco / email security appliance
Certified products that may be affected
4 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.
- Cisco Email Security Appliance with AsyncOS 13.0 - Cisco Systems, Inc. - Common Criteria 495-LSS - archived
- Cisco Email Security Appliance 9.8 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10798-2017 - archived
- Cisco Email Security Appliance v9.1 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10631-2015 - archived
- IronPort Email Security Appliances (ESA), comprising the C160, C370, X1060, and X1070 appliance models, running IronPort AsyncOS software, version 7.1, and the C670 appliance model running IronPort AsyncOS version 7.3 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10438-2010 - archived
References
Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS
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