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Fencer Intel
high 7.7

CVE-2021-1422 json

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

published 5y ago modified 2mo ago also EUVD-2021-6889

cvss
7.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits
0
none known

Summary

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.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2y ago

Exploit prediction

1.20% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
NVD 3.1 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
NVD 2.0 6.8 AV:N/AC:L/Au:S/C:N/I:N/A:C

Affected products

  • Cisco Cisco Adaptive Security Appliance (ASA) Software

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.