CVE-2021-1422

Cisco Adaptive Security Appliance Software Release 9.16.1 and Cisco Firepower Threat Defense Software Release 7.0.0 IPsec Denial of Service Vulnerability

HIGH
7.7
CVSS Score
Published: July 16, 2021 at 12:25 PM UTC
Updated: August 11, 2026 at 07:42 PM UTC
9 products affected across 1 vendorAdaptive Security ApplianceSecure Firewall Threat DefenseFirepower 2110

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Severity
HIGH7.7
Exploit prediction
EPSS 1%
SSVC
No known exploit

Description

A vulnerability in the software cryptography module of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker or an unauthenticated attacker in a man-in-the-middle position to cause an unexpected reload of the device that results in a denial of service (DoS) condition. The vulnerability is due to a logic error in how the software cryptography module handles specific types of decryption errors. An attacker could exploit this vulnerability by sending malicious packets over an established IPsec connection. A successful exploit could cause the device to crash, forcing it to reload. Important: Successful exploitation of this vulnerability would not cause a compromise of any encrypted data. Note: This vulnerability affects only Cisco ASA Software Release 9.16.1 and Cisco FTD Software Release 7.0.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

cisco-adaptive-security-virtual-appliance (environment) · cisco-firepower-2100 (environment) · cisco-firepower-2110 (environment) · cisco-firepower-2120 (environment) · cisco-firepower-2130 (environment) · cisco-firepower-2140 (environment) · cisco-ftd-virtual (environment)
cisco-adaptive-security-virtual-appliance (environment) · cisco-firepower-2100 (environment) · cisco-firepower-2110 (environment) · cisco-firepower-2120 (environment) · cisco-firepower-2130 (environment) · cisco-firepower-2140 (environment) · cisco-ftd-virtual (environment)
All versions
All versions
All versions
All versions
All versions
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.7HIGHcisco
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-617

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