Threat Intelligence / CVE / CVE-2025-40551

CVE-2025-40551 — Solarwinds Web Help Desk

CISA KEV

CVSS v3.1 9.8 (CRITICAL) · EPSS 89.9% (higher than 99.5% of all scored CVEs) · Priority 9/10 · Published 2026-01-28

As of 2026-02-04, CVE-2025-40551 is a CRITICAL-severity vulnerability in Solarwinds Web Help Desk, CVSS v3.1 9.8, EPSS 89.9% (99.5th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-02-03), with a US federal remediation deadline of 2026-02-06. Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2025-40551, most recently “SolarWinds Web Help Desk Deserialization RCE - CISA KEV”.

Last updated: 2026-02-04

What is CVE-2025-40551?

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.

The record classifies CVE-2025-40551 under weakness class CWE-502. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 228 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (FIRST): 89.9% probability of exploitation in the next 30 days, higher than 99.5% of all scored CVEs
CISA KEV: Listed since 2026-02-03, federal remediation deadline 2026-02-06
Threadlinqs priority: 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
Published: 2026-01-28, last modified 2026-02-04

Is CVE-2025-40551 being exploited?

CISA added CVE-2025-40551 to the Known Exploited Vulnerabilities catalog on 2026-02-03, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-02-06 under BOD 22-01. It currently carries a trending score of 40 in the Threadlinqs vulnerability feed.

Affected products and versions

Solarwinds: Web Help Desk

How to fix CVE-2025-40551

Vendor advisory: https://www.solarwinds.com/trust-center/security-advisories/CVE-2025-40551. Because CVE-2025-40551 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-02-06. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2025-40551

2 tracked threats in the Threadlinqs corpus reference CVE-2025-40551, either in the campaign’s CVE list or as an indicator on the campaign record.

SolarWinds Web Help Desk Deserialization RCE - CISA KEV — CRITICAL · 2026-02-03
SolarWinds Access Rights Manager (ARM) Systemic Deserialization RCE — 17 CVEs, 6 Unauth SYSTEM RCE, Access Control Paradox — CRITICAL · 2026-02-02

Sources

Seeded from nvd and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

Full detection coverage & IOCs for threats exploiting CVE-2025-40551 are available via the Threadlinqs MCP server (Purple tier). View plans →

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