CVE-2022-20760Network attack vector

Device hang via high-rate crafted DNS requests

Published May 3, 2022 · Updated Nov 6, 2024

Denial of service in Cisco ASA Software's DNS inspection handler allows remote attackers to stop devices via crafted DNS requests. The handler improperly processes high-rate incoming DNS requests until the affected device stops responding. No authentication is required, but DNS inspection must be enabled; Cisco states that the feature is enabled by default, and the reported consequence is a device hang.

CVSS severity8.6
High
EPSS probability1.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Cisco ASA Software's DNS inspection handler allows remote attackers to stop devices via crafted DNS requests. The handler improperly processes high-rate incoming DNS requests until the affected device stops responding. No authentication is required, but DNS inspection must be enabled; Cisco states that the feature is enabled by default, and the reported consequence is a device hang.

The record

CVE
CVE-2022-20760
Published
May 3, 2022
Updated
Nov 6, 2024
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-400, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 3, 2022CVE publishedPublication date reported by the CVE source.
  2. Nov 6, 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?

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  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

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.8NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:C
8.6CiscoCVSS:3.1/AV:N/AC:L/PR:N/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.

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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-400Uncontrolled Resource Consumption
T1499.002Service Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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