CVE intelligence and bounded remediation

CVE-2021-25274 — Solarwinds Orion Platform security vulnerability

Critical CVSS 9.8

The Collector Service in SolarWinds Orion Platform before 2020.2.4 uses MSMQ (Microsoft Message Queue) and doesn't set permissions on its private queues. As a result, remote unauthenticated clients can send messages to TCP port 1801 that the Collector Service will process. Additionally, upon processing of such messages, the service deserializes them in insecure manner, allowing remote arbitrary code execution as LocalSystem.

Severity
Critical
CVSS
9.8 (3.1)
Published
2021-02-03
CISA KEV
Not currently listed
Ecosystem
windows/system
Weaknesses
CWE-502

Affected products

  • solarwinds / orion_platform

Matched remediation archetype

Unsafe deserialization and object reconstruction

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Check exposure

  • Inventory serialization formats accepted from requests, queues, caches, files, cookies, and cross-service messages.
  • Trace whether untrusted input can select classes, types, callbacks, constructors, or object hooks during decoding.
  • Identify signing, schema validation, trust-boundary, and compatibility settings for each decoder.

Remediate safely

  • Replace native object deserialization with a data-only format and explicit schema validation.
  • If replacement is not immediate, use a safe decoder with a minimal type allowlist and disable polymorphic or executable hooks.
  • Update the affected library and add inert tests for unknown types, extra fields, malformed nesting, and unsigned data.

Authoritative sources

Complete CVE record and remediation plan

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