CVE-2021-40117
Medium
Elevated severity or exploit probability.
CVSS base
8.6
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS — probability of exploitation (30 days)
1.5%
73.6th percentile
CISA KEV
Not listed
Weakness / dates
CWE-400
Published 2021-10-27 · modified 2026-08-11
CVSS breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
| Attack Vector | N | Network |
| Attack Complexity | L | Low |
| Privileges Required | N | None |
| User Interaction | N | None |
| Scope | C | Changed |
| Confidentiality | N | None |
| Integrity | N | None |
| Availability | H | High |
Timeline
- 2021-10-27 — Published (NVD)
- 2026-08-11 — Last modified (NVD)
Description
A vulnerability in SSL/TLS message handler for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability exists because incoming SSL/TLS packets are not properly processed. An attacker could exploit this vulnerability by sending a crafted SSL/TLS packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.