CVE-2025-26399
SolarWinds Web Help Desk Deserialization of Untrusted Data Vulnerability
SolarWinds Web Help Desk
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.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 9 March 2026. US federal agencies were required to remediate it by 12 March 2026. CISA records this vulnerability as known to be used in ransomware campaigns.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 90.6%, which is higher than 99.8% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Frequently asked questions
Is CVE-2025-26399 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2025-26399.
What does CVE-2025-26399 affect?
CVE-2025-26399 affects SolarWinds Web Help Desk. 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.
How severe is CVE-2025-26399?
CVE-2025-26399 is rated CRITICAL with a CVSS base score of 9.8. EPSS puts the probability of exploitation in the next 30 days at 90.6%, higher than 99.8% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 12 March 2026.
How should organisations respond to CVE-2025-26399?
Apply the vendor patch for SolarWinds Web Help Desk as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.