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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.85%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.85% probability · 58th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-400, CWE-295
- Affected
- cisco/email security appliance
- Source
- psirt@cisco.com
EPSS 0.8% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.