Unauthenticated RCE in SolarWinds Web Help Desk Deserialization
CVE-2025-40551 is a critical deserialization of untrusted data vulnerability in SolarWinds Web Help Desk (WHD). The flaw affects SolarWinds Web Help Desk 12.8.8 HF1 and all previous versions, and was fixed in WHD version 2026.1. According to the provided content, the issue allows untrusted serialized data to be processed in a way that can be abused by a remote attacker to achieve code execution on the underlying host. Exploitation does not require authentication. The vulnerability has been described by SolarWinds and downstream reporting as an unauthenticated Java deserialization issue leading to remote code execution, and it has been added to CISA’s Known Exploited Vulnerabilities catalog due to active exploitation in the wild.
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Impact, mitigation & remediation
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Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
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Remediation
Patch, then assume compromise.
Exploits
No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.
All candidate exploits were filtered out by Mallory's validation.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
149 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A SolarWinds Web Help Desk vulnerability actively exploited to enable persistence, reconnaissance, and deployment of remote management tooling and Velociraptor C2.
A critical vulnerability in SolarWinds Web Help Desk (WHD) reported as being exploited by unknown attackers against internet-exposed instances, enabling initial access and subsequent lateral movement.
A critical vulnerability in SolarWinds Web Help Desk (WHD) reported as being exploited by unknown attackers; described as a 9.8-rated flaw and associated with intrusions against internet-exposed WHD instances.
Recently disclosed SolarWinds Web Help Desk vulnerability potentially used for initial access in observed multi-stage intrusions (exact CVE used not confirmed in the content).
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.