A critical vulnerability (CVE-2025-26399) has been identified in SolarWinds Web Help Desk, which allows unauthenticated remote attackers to execute arbitrary code on affected systems. Although CVE-2025-26399 was originally disclosed in 2025, recent reports confirm this vulnerability is now being actively exploited in the wild. This development significantly elevates the risk to impacted environments. Immediate remediation is required to prevent compromise. 

What do I need to know? 

  • CVE ID: CVE-2025-26399  
  • Severity: Critical (CVSS 3.1 Score: 9.8)  
  • Attack Vector: Network  
  • Attack Complexity: Low  
  • Privileges Required: None  
  • User Interaction: None  
  • Impact: Full compromise of confidentiality, integrity, and availability  
  • Root Cause: Insecure deserialization of Untrusted Data (CWE-502) in the AjaxProxy component

Products & Systems Affected 

  • Earliest Patched Version:  
    12.8.7 Hotfix 1 
  • Exploit Status: 
    Actively exploited; listed in CISA’s Known Exploited Vulnerabilities Catalog  
  • Related CVEs: 
    CVE-2025-26399 is a bypass of patches for CVE-2024-28988 and CVE-2024-28986 

What do I need to do? 

We recommend the following steps to identify and remediate this vulnerability: 

  • Apply the vendor patch: 
  • If patching is not immediately possible:  
    • Restrict network access to the Web Help Desk server. 
    • Monitor for suspicious activity, including unexpected process execution and outbound connections. 
  • Audit and Monitor:  
    • Review logs for signs of exploitation attempts. 
    • Implement additional endpoint detection and response (EDR) monitoring for anomalous behavior. 

NetSPI Product and Services Coverage 

NetSPI’s External Attack Surface Management is issuing a version-based detection for this CVE, which will present as: Vulnerable Version – SolarWinds Web Help Desk Insecure Deserialization (CVE-2025-26399). 

NetSPI’s Penetration Testing Services can also help identify exposure to this vulnerability.