CVE-2020-3170Network attack vector

NX-API service interruption via malformed HTTP header

Published Feb 26, 2020 · Updated Nov 15, 2024

Improper HTTP header validation in Cisco NX-OS Software allows remote attackers to restart the NX-API process with a crafted request. The external NX-API accepts a crafted HTTP or HTTPS header without correct validation, causing its system process to restart. NX-API must be enabled, although it is disabled by default; exploitation interrupts only that service while the device keeps passing traffic.

CVSS severity5.3
Medium
EPSS probability1.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper HTTP header validation in Cisco NX-OS Software allows remote attackers to restart the NX-API process with a crafted request. The external NX-API accepts a crafted HTTP or HTTPS header without correct validation, causing its system process to restart. NX-API must be enabled, although it is disabled by default; exploitation interrupts only that service while the device keeps passing traffic.

The record

CVE
CVE-2020-3170
Published
Feb 26, 2020
Updated
Nov 15, 2024
Vendor
ClamAV
Product
Cisco NX-OS Software
Classifications
CWE-20, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 26, 2020CVE publishedPublication date reported by the CVE source.
  2. Nov 15, 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=unspecified <n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco NX-OS Softwareversion=unspecified <n/a

Published CVSS scores

5.3National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
4.3National Vulnerability DatabaseAV:N/AC:M/Au:N/C:N/I:N/A:P
5.3Cisco Systems, Inc.CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499Endpoint Denial of Service

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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