CVE-2025-26399

SolarWinds Web Help Desk Deserialization of Untrusted Data Privilege Escalation Vulnerability

Critical 9.8
Exploited: added to CISA KEV 9 Mar 2026
Used in ransomware campaigns

Description

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.

Key facts

Published: 23 Sep 2025
Last changed: 4 Aug 2026
Assigned by: SolarWinds
KEV added: 9 Mar 2026
KEV fix due: 12 Mar 2026
Used in ransomware: Yes, according to CISA
EPSS: 90.564% likely to be exploited in the next 30 days, higher than 99.805% of CVEs (scores for 15 Nov 2026)
SSVC (CISA): Exploitation: active; Automatable: yes; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

9.8CVSS 3.1, Criticalfrom the CNA (SolarWinds)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

What to do

SolarWinds recommends customers to upgrade to Web Help Desk version 12.8.7 HF1 as soon as is practical.CNA solution statement
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

CAPEC-248: Untrusted Execution Flow (CNA impact statement)

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

Vendor	Product	Versions
SolarWinds	Web Help Desk	Default status: unaffected 12.8.7 and below (affected)