CVE-2025-40551

SolarWinds Web Help Desk remote code execution, confirmed exploited in the wild.

SolarWinds Web Help Desk contains a deserialization of untrusted data 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.

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84%chance of exploitation in the next 30 days (EPSS), 99th percentile

3 Febadded to CISA's Known Exploited Vulnerabilities list, 2026

6 Febfederal remediation deadline, already passed

Passedpast the deadline: patch now

CISA's name for it	SolarWinds Web Help Desk Deserialization of Untrusted Data Vulnerability
Vendor and product	SolarWinds · Web Help Desk
Type	remote code execution · CWE-502
Exploited	Confirmed by CISA listed 3 February 2026
Likelihood	one of the most likely to be exploited of every vulnerability tracked
Deadline	6 February 2026 · already passed
Used in ransomware	Not reported
Advisories	www.solarwinds.com ↗ · nvd.nist.gov ↗

What to do

Three steps, in this order

Step 1

Patch to the fixed version the vendor names, today if the product faces the internet.

Step 2

Until it is patched, take the affected service off the internet or put it behind a VPN or allow-list.

Step 3

Look for signs it was already used: new accounts, web shells, unexpected processes and outbound connections since the date it was listed.

CISA's required action	Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

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Questions

CVE-2025-40551 in short

Is CVE-2025-40551 being exploited?

Yes. CISA added CVE-2025-40551 to its Known Exploited Vulnerabilities catalogue on 3 February 2026, which it does only on evidence of exploitation in the wild.

What is the CISA deadline for CVE-2025-40551?

US federal agencies must remediate it by 6 February 2026. Everyone else should treat that date as the latest safe point to patch an internet-facing system.

How likely is CVE-2025-40551 to be exploited in the next 30 days?

FIRST's Exploit Prediction Scoring System gives it 84%, the 99th percentile of every CVE it scores.

How do I fix CVE-2025-40551?

Patch to the fixed version the vendor names, today if the product faces the internet. Until it is patched, take the affected service off the internet or put it behind a VPN or allow-list. Look for signs it was already used: new accounts, web shells, unexpected processes and outbound connections since the date it was listed.

Same vendor

Other SolarWinds vulnerabilities being exploited

CVE	Product	Type	Listed
CVE-2026-28318	Serv-U	exploited vulnerability	5 June 2026
CVE-2025-26399	Web Help Desk	insecure deserialization	9 March 2026
CVE-2025-40536	Web Help Desk	exploited vulnerability	12 February 2026

Sources: CISA Known Exploited Vulnerabilities catalogue (released 10 November 2026) and FIRST EPSS. Page compiled automatically by SAK T.L.M, the threat-intelligence tool of SAK T.E.C, on 13 November 2026.