Deserialization in Solarwinds Web Help Desk

CVE-2025-26399

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…

Vulnerability class: Insecure Deserialization

EPSS: 0.267 (96.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: .

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.

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-26399?
CVE-2025-26399 is a critical-severity vulnerability in Solarwinds Web Help Desk, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2025-09-23.
How severe is CVE-2025-26399?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2025-26399 known to be exploited?
Yes. CVE-2025-26399 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-03-09), indicating it is being actively exploited. 7 public proof-of-concept repositories are indexed.