CVE-2025-26399

SolarWinds Web Help Desk: Deserialization of Untrusted Data

As of , CVE-2025-26399 in SolarWinds Web Help Desk is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch now.

Exploited
Yes: CISA listed it on 9 March 2026
US federal deadline
12 March 20263 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
KnownCISA changed it from Unknown to Known on 4 August 2026.
EPSS score
0.90Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
Vendor advice: documentation.solarwinds.com and www.solarwinds.comLinks below, from CISA's entry.

What CISA says to do

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's required action

What the flaw is

SolarWinds Web Help Desk contain a deserialization of untrusted data vulnerability in AjaxProxy that could allow an attacker to run commands on the host machine.

CISA's 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.

The CVE record's description, from SolarWinds

CVE published
23 September 2025
Assigned by
SolarWinds
CVSS
9.8 Critical (CVSS 3.1, from the CNA)
CWE-502
Deserialization of Untrusted Data
CISA SSVC, exploitation
active
CISA SSVC, automatable
yes
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.
  4. CISA changed its entry. Ransomware use: Unknown to Known.

Web Help Desk: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2025-40536Security Control BypassSolarWinds Web Help DeskPatch this weekMetasploit module; EPSS 0.740.74
CVE-2025-40551Deserialization of Untrusted DataSolarWinds Web Help DeskPatch this weekMetasploit module; EPSS 0.840.84
CVE-2024-28987Hardcoded CredentialSolarWinds Web Help DeskPatch this weekMetasploit module; EPSS 0.930.93
CVE-2024-28986Deserialization of Untrusted DataSolarWinds Web Help DeskPatch this weekEPSS 0.850.85

Read further