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CVE-2025-26399

9.8, critical Known exploited Used in ransomware

SolarWinds Web Help Desk Deserialization of Untrusted Data Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab) CISA KEV catalogue (opens in a new tab)
CVSS
9.8, critical critical CVSS v3.1
EPSS, next 30 days
90% higher than 99.7% of scored CVEs
Exploitation
Confirmed in the wild
Published
23 Sept 2025a year ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 9 Mar 2026 and links it to ransomware activity. US federal agencies had to remediate by 12 Mar 2026, a deadline that has passed.

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

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.

Details

Vendor
SolarWinds
Product
Web Help Desk
Weakness
CWE-502 (opens in a new tab)
Status
Analyzed
Updated
11 Oct 2026
Assigner
psirt@solarwinds.com

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References 4

Patches and fixes 1

Advisories 1

Other references 2

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other SolarWinds CVEs

Every SolarWinds CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2026-28318 SolarWinds Serv-U Uncontrolled Resource Consumption Vulnerability KEV EPSS 2% 7.5, high
  • CVE-2025-40536 SolarWinds Web Help Desk Security Control Bypass Vulnerability KEV EPSS 74% 9.8, critical
  • CVE-2025-40551 SolarWinds Web Help Desk Deserialization of Untrusted Data Vulnerability KEV EPSS 84% 9.8, critical
  • CVE-2024-28987 SolarWinds Web Help Desk Hardcoded Credential Vulnerability KEV EPSS 93% 9.1, critical
  • CVE-2024-28986 SolarWinds Web Help Desk Deserialization of Untrusted Data Vulnerability KEV EPSS 85% 9.8, critical
  • CVE-2024-28995 SolarWinds Serv-U Path Traversal Vulnerability KEV EPSS 100% 7.5, high
  • CVE-2021-35247 SolarWinds Serv-U Improper Input Validation Vulnerability KEV EPSS 3% 5.3, medium
  • CVE-2021-35211 SolarWinds Serv-U Remote Code Execution Vulnerability KEV EPSS 91% 10, critical

Beyond this page

Is CVE-2025-26399 in your network?

This page tells you how dangerous CVE-2025-26399 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2025-26399 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

  • EXYS7600 OCELOT

    Find it before attackers do

    Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2025-26399 comes with the devices to patch.

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

    Learn more about EXYS7950 KONDRA
Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.