CVE-2021-25274Public exploit

Unauthenticated LocalSystem code execution via MSMQ deserialization

Published Feb 3, 2021 · Updated Aug 3, 2024

Deserialization in the Collector Service in SolarWinds Orion Platform before 2020.2.4 allows remote attackers to execute code as LocalSystem. The service accepts unsigned messages on unauthenticated private MSMQ queues over TCP port 1801 and deserializes their untrusted contents. Network access to MSMQ is sufficient, and successful exploitation runs arbitrary code with LocalSystem privileges on the Windows host.

CVSS severity8.3
High
EPSS probability36.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in the Collector Service in SolarWinds Orion Platform before 2020.2.4 allows remote attackers to execute code as LocalSystem. The service accepts unsigned messages on unauthenticated private MSMQ queues over TCP port 1801 and deserializes their untrusted contents. Network access to MSMQ is sufficient, and successful exploitation runs arbitrary code with LocalSystem privileges on the Windows host.

The record

CVE
CVE-2021-25274
Published
Feb 3, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-502, T1210
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 3, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.3SolarWindsCVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C

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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1210Exploitation of Remote Services

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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