CVE intelligence and bounded remediation

CVE-2021-27277 — Solarwinds Orion Platform security vulnerability

High CVSS 7.8

This vulnerability allows local attackers to escalate privileges on affected installations of SolarWinds Orion Virtual Infrastructure Monitor 2020.2. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the OneTimeJobSchedulerEventsService WCF service. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-11955.

Severity
High
CVSS
7.8 (3.1)
Published
2021-04-22
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-502

Affected products

  • solarwinds / orion_platform / 2020.2

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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