Cyber Resilience

CVE-2021-35216

Deserialization in Solarwinds Patch Manager ≤ 2020.2.6

Published
01 September 2021
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 8.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
EPSS Score 0.81 99.6th percentile
Risk Priority 84 floored blend · peak EPSS

Summary

CVE-2021-35216 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Solarwinds Patch Manager. Its CVSS base score is 8.9 (High).

Operationally, ranked in the top 0.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Insecure Deserialization of untrusted data remote code execution vulnerability was discovered in Patch Manager Orion Platform Integration module. An Authenticated Attacker with network access via HTTP can compromise this vulnerability can result in Remote Code Execution.

CWE(s)

Related Threats

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1190 Exploit Public-Facing Application Initial Accessconfidence: HIGH
Insecure deserialization of untrusted data over HTTP directly enables remote code execution against a public-facing application.
T1059 Command and Scripting Interpreter Executionconfidence: MEDIUM
Successful exploitation yields arbitrary command execution on the target system.
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2021-35217Same product: Solarwinds Patch Manager
CVE-2021-31474Same product class: network monitoring / SIEM
CVE-2025-26399Same product class: network monitoring / SIEM
CVE-2023-35184Same product class: network monitoring / SIEM
CVE-2024-28991Same product class: network monitoring / SIEM
CVE-2024-28988Same product class: network monitoring / SIEM
CVE-2024-23478Same product class: network monitoring / SIEM
CVE-2023-35180Same product class: network monitoring / SIEM
CVE-2023-35182Same product class: network monitoring / SIEM
CVE-2023-23836Same product class: network monitoring / SIEM

Affected Assets

solarwinds
patch manager
≤ 2020.2.6

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-502

Penetration testing supplies malicious serialized objects, detecting unsafe deserialization and supporting corrective actions.

addresses: CWE-502

Evaluation of untrusted data handling (deserialization testing) reveals unsafe processing, which the required remediation process addresses.

addresses: CWE-502

Untrusted serialized data can be deserialized and observed inside the chamber, blocking gadget-chain exploitation outside the sandbox.

addresses: CWE-502

Validates or rejects untrusted serialized data before deserialization occurs.

addresses: CWE-502

Identifies and blocks malicious code introduced through deserialization of untrusted data at system boundaries.

addresses: CWE-502

Integrity verification of serialized information can detect tampering before deserialization occurs.

addresses: CWE-502

Provenance of associated data allows detection of untrusted sources before deserialization or processing occurs.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-02 none match
prevents

PR.PS-02 addresses only post-deployment updates/patching and cannot prevent introduction of unsafe deserialization code, yet it can remediate some instances when the flaw exists in outdated libraries or components.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

detects

Security testing includes validation of deserialization routines and the use of untrusted data, reducing the likelihood that unsafe object reconstruction will be deployed.

prevents

Requiring vetted libraries, regular updates and SAST before release reduces the likelihood that deserialization logic will accept and act on attacker-controlled serialized objects.

detects

Regular scanning of third-party libraries and timely patching reduce the likelihood that unsafe deserialization vulnerabilities remain active.

none

Mandatory malware scanning of data received over networks or storage media intercepts malicious serialized payloads before they are deserialized by the target application.

References