SolarWinds Web Help Desk Patch Bypass Leaves Actively Exploited Flaw Exposed
SolarWinds issued another fix for Web Help Desk after attackers were found exploiting a patch bypass that left a previously addressed vulnerability still reachable. The report says the flaw was being actively exploited, forcing the company to reissue remediation guidance and update customers again to close the bypass condition.
The incident highlights the operational risk of incomplete vulnerability remediation, where an initial patch can be circumvented and exposed systems remain vulnerable despite prior updates. Organizations running Web Help Desk were urged to apply the latest vendor fix immediately and verify that earlier mitigations had not left the product exposed to continued exploitation.
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How this story unfolded
3 events from the most recent confirmed update back to the earliest known activity.
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SolarWinds issues another fix for exploited Web Help Desk patch bypass
SolarWinds released an additional fix for an actively exploited Web Help Desk vulnerability after a prior patch was found to be bypassable. The CSO Online report indicates the flaw was under active exploitation at the time of the renewed fix.
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Active Exploitation of SolarWinds Web Help Desk Flaws Enables Remote Code Execution
SolarWinds warned that multiple vulnerabilities in **Web Help Desk** are being actively exploited, with reporting highlighting a critical flaw that can lead to **remote code execution** on exposed help-desk servers. Public references tie the activity to `CVE-2025-40554`, while additional SolarWinds advisories and third-party research point to related issues including `CVE-2025-40552`, `CVE-2025-40553`, and `CVE-2025-40536`, indicating a broader security problem affecting the product. Security researchers and defenders published proof-of-concept material and detection guidance shortly after disclosure, including a watchTowr repository focused on Web Help Desk exploitation and a GitHub Gist describing **uncommon process activity** associated with compromise. The combination of vendor advisories, media reporting, and public exploit research indicates that attackers moved quickly to weaponize the flaws, increasing risk for organizations that have not patched, isolated, or monitored SolarWinds Web Help Desk deployments.
Jul 1, 2026
Active Exploitation of SolarWinds Web Help Desk Insecure Deserialization (CVE-2025-26399)
**CVE-2025-26399** is a **critical insecure deserialization** flaw (CWE-502) in *SolarWinds Web Help Desk* that enables **unauthenticated remote code execution/command execution** over the network. The issue resides in the product’s **`AjaxProxy`** component, where untrusted serialized data can be processed without sufficient validation, allowing an attacker to deliver a crafted payload that results in arbitrary command execution on the host running the help desk application. Multiple reports indicate the vulnerability is **actively exploited in the wild**, prompting **CISA** to add CVE-2025-26399 to the **Known Exploited Vulnerabilities (KEV)** catalog. NetSPI notes the flaw was disclosed in 2025 and is described as a **patch bypass** related to earlier issues (**CVE-2024-28988** and **CVE-2024-28986**), and recommends immediate remediation by upgrading to **SolarWinds Web Help Desk 12.8.7 Hotfix 1 or later**; if patching is delayed, organizations should restrict network exposure of the server and increase monitoring for suspicious process execution and outbound connections.
Jun 29, 2026
Critical RCE and Authentication Bypass Vulnerabilities in SolarWinds Web Help Desk
SolarWinds released security updates for *Web Help Desk (WHD)* to address multiple critical vulnerabilities that could allow **unauthenticated remote attackers** to bypass authentication and achieve **remote code execution (RCE)**. The patched issues include two critical authentication bypass flaws, **CVE-2025-40552** and **CVE-2025-40554** (reported by watchTowr researcher Piotr Bazydlo), and two critical RCE flaws tied to **untrusted data deserialization**, **CVE-2025-40553** (Bazydlo) and **CVE-2025-40551** (reported by Horizon3.ai researcher Jimi Sebree), enabling remote command execution without prior access. SolarWinds also fixed a high-severity **hardcoded credentials** issue, **CVE-2025-40537**, which could enable unauthorized access to administrative functions under certain conditions. The vendor advised administrators to upgrade to **Web Help Desk 2026.1** and patch quickly, noting WHD has a history of being targeted and previously had vulnerabilities flagged as actively exploited by CISA, reinforcing the likelihood of rapid attacker interest following disclosure and patch availability.
Jun 29, 2026