What is the CVSS score of CVE-2025-40553?

CVE-2025-40553 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 11.9%.

Is there a public PoC exploit available for CVE-2025-40553?

Yes, a public proof-of-concept exploit is available for CVE-2025-40553. Prioritise patching immediately. EPSS: 11.9%.

How to fix or mitigate CVE-2025-40553?

Within 24 hours: Identify all SolarWinds Web Help Desk instances in production and isolate affected systems from untrusted networks. Implement network segmentation and restrict access to administrative interfaces. Within 7 days: Deploy network-based mitigations (WAF rules blocking deserialization payloads), disable remote access features if not business-critical, and enable enhanced logging and monitoring. Within 30 days: Evaluate alternative help desk solutions, prepare for vendor patch deployment, and conduct security assessment of affected systems for signs of compromise.

Web Help Desk CVE-2025-40553

CRITICAL

Deserialization of Untrusted Data (CWE-502)

2026-01-28 psirt@solarwinds.com

RCE Deserialization Web Help Desk Solarwinds

9.8

CVSS 3.1 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-502 OWASP Top 10:2025 A08:2025 - Software or Data Integrity Failures ASVS 5.0 V1 - Encoding and Sanitization Safe deserialization, type allowlists MITRE ATT&CK 2 techniques across 2 tactics: Execution, Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS 9.8, EPSS 11.9%. Third of four critical WHD vulnerabilities. Even if one deserialization path is patched, this provides an alternate exploitation route.
Exploit ScenarioDerived	An attacker uses this alternative deserialization vector when CVE-2025-40551 is blocked, achieving the same RCE outcome through a different code path.

Act Now Prioritize within 24-48h. Why: CRITICAL + active threat signals, no patch available.

No patch listed yet 11.9% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

SolarWinds Web Help Desk has a second deserialization vulnerability (EPSS 11.9%) providing another unauthenticated RCE path alongside CVE-2025-40551.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:54 CVSS 9.8

Second deserialization RCE in SolarWinds WHD — additional attack vector.

RemediationAI

Apply patches for all four WHD vulnerabilities.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

A separate CWE-502 deserialization vulnerability in SolarWinds WHD, distinct from CVE-2025-40551 but with the same impact: unauthenticated remote code execution through crafted serialized objects.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionCVE.org

SolarWinds Web Help Desk was found to be susceptible to an untrusted data deserialization vulnerability that could lead to remote code execution, which would allow an attacker to run commands on the host machine. This could be exploited without authentication.

Executive ViewAI

Why It Matters

A critical remote code execution vulnerability in SolarWinds Web Help Desk allows unauthenticated attackers to execute arbitrary commands on affected systems. Organizations using this product face immediate risk of system compromise, data theft, and operational disruption. With no patch currently available, immediate containment actions are required to prevent exploitation.

Business Impact: Severe

Compensating Controls

Implement Web Application Firewall (WAF) rules to detect and block serialized Java object payloads; restrict network access to Web Help Desk via IP whitelisting and VPN-only access; disable unnecessary remote features and API endpoints; segment affected systems from critical infrastructure; deploy endpoint detection and response (EDR) to monitor for suspicious process execution; increase logging and threat monitoring for exploitation attempts; consider temporary service shutdown until patch availability if business continuity permits.

Threat Intelligence Overview

EPSS Score

11.9%

Top 6% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV No

Public POC Yes

EPSS 11.9%

Patch available No

Active threat Yes

Deciding rule

CRITICAL + active threat signals, no patch available

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Out-of-Cycle

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

Very High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +12

CVSS: +49

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Insecure Deserialization CRITICAL

Insecure deserialization occurs when an application converts serialized data (a stream of bytes representing an object's state) back into a living object without proper validation.

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.