CVE-2021-31474Public exploitNetwork attack vector

Authenticated SYSTEM code execution via unsafe FromJson deserialization

Published May 21, 2021 · Updated Aug 3, 2024

Unsafe deserialization in SolarWinds Network Performance Monitor 2020.2.1 allows remote authenticated users to execute code as SYSTEM. The /api/Action/TestAction endpoint passes attacker-controlled JSON type data to SolarWinds.Serialization FromJson without validating permitted types. A valid web-console session is required, and successful exploitation runs arbitrary code with full SYSTEM privileges.

CVSS severity9.1
Critical
EPSS probability94.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsafe deserialization in SolarWinds Network Performance Monitor 2020.2.1 allows remote authenticated users to execute code as SYSTEM. The /api/Action/TestAction endpoint passes attacker-controlled JSON type data to SolarWinds.Serialization FromJson without validating permitted types. A valid web-console session is required, and successful exploitation runs arbitrary code with full SYSTEM privileges.

The record

CVE
CVE-2021-31474
Published
May 21, 2021
Updated
Aug 3, 2024
Vendor
SolarWinds
Product
Network Performance Monitor
Classifications
CWE-502, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=2020.2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

SolarWinds · Network Performance Monitorversion=2020.2.1

Published CVSS scores

9.8Zero Day InitiativeCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.1SolarWindsCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L
10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

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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