CVE-2025-26399criticalunder attackransomwareCWE-502

CVE-2025-26399: critical vulnerability in SolarWinds Web Help Desk

SolarWinds Web Help Desk Deserialization of Untrusted Data Privilege Escalation Vulnerability

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100Vexday Risk Score

Patch now. It under exploitation confirmed by CISA and has a working public exploit.

ssvc Actcvss 9.8epss 91%
from disclosure to weaponsame day
Published on NVDSep 23
1st PoCSep 23
CISA KEV+167d
Action required by CISAfederal deadline: 2026-03-12

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

In short

SolarWinds Web Help Desk allows attackers to run commands on servers without authentication by exploiting unsafe data deserialization in the AjaxProxy component. This is a critical flaw because it completely bypasses the system's security, letting intruders take full control.

Technical detail

An unauthenticated attacker can exploit unsafe deserialization (CWE-502) in the AjaxProxy endpoint to achieve remote code execution with system privileges. This vulnerability chains privilege escalation and bypasses previous patches (CVE-2024-28988, CVE-2024-28986), requiring no authentication or user interaction.

Summary generated and translated by AI from the official description.

The full analysis of this CVE is available in Portuguese →

SolarWinds Web Help Desk was found to be susceptible to an unauthenticated AjaxProxy deserialization remote code execution vulnerability that, if exploited, would allow an attacker to run commands on the host machine. This vulnerability is a patch bypass of CVE-2024-28988, which in turn is a patch bypass of CVE-2024-28986.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
SolarWinds · Web Help Desk
⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
Related CVEs — SolarWinds Web Help Desk

In the same product, most dangerous first.

CVE-2024-28987CRITICALSolarWinds Web Help Desk Hardcoded Credential VulnerabilityEPSS 93.3%KEVCVE-2024-28986CRITICALSolarWinds Web Help Desk Java Deserialization Remote Code Execution VulnerabilityEPSS 84.6%KEVCVE-2025-40551CRITICALSolarWinds Web Help Desk Deserialization of Untrusted Data Remote Code Execution VulnerabilityEPSS 84.2%KEVCVE-2025-40536HIGHSolarWinds Web Help Desk Security Control Bypass VulnerabilityEPSS 73.6%KEVCVE-2025-40553CRITICALSolarWinds Web Help Desk Deserialization of Untrusted Data Remote Code Execution VulnerabilityEPSS 68.0%CVE-2025-40554CRITICALSolarWinds Web Help Desk Authentication Bypass VulnerabilityEPSS 60.6%