CVE-2021-1422Network attack vector

Device reload via mishandled IPsec decryption errors

Published Jul 16, 2021 · Updated Nov 7, 2024

Reachable assertion in Cisco ASA Software 9.16.1 allows remote attackers to crash and reload an IPsec-enabled device. The software cryptography module mishandles specific decryption errors from malicious packets on an established IPsec connection, triggering the assertion and device crash. Exploitation requires authenticated IPsec access or a man-in-the-middle position; FIPS-enabled devices are unaffected, and encrypted data remains protected.

CVSS severity7.7
High
EPSS probability1.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in Cisco ASA Software 9.16.1 allows remote attackers to crash and reload an IPsec-enabled device. The software cryptography module mishandles specific decryption errors from malicious packets on an established IPsec connection, triggering the assertion and device crash. Exploitation requires authenticated IPsec access or a man-in-the-middle position; FIPS-enabled devices are unaffected, and encrypted data remains protected.

The record

CVE
CVE-2021-1422
Published
Jul 16, 2021
Updated
Nov 7, 2024
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 16, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 7, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Adaptive Security Appliance (ASA) Softwareversion=n/a

Published CVSS scores

6.8NVDAV:N/AC:L/Au:S/C:N/I:N/A:C
7.7Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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