PatchTheCVECVE-2025-26399: SolarWinds Web Help Desk Deserialization of Untrusted Data Vulnerability
CVE-2025-26399 is a critical-severity flaw (CVSS 9.8) affecting web help desk, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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.
Why this priority
- Critical severity
- EPSS top 1%: very likely to be exploited
- Exploited in the wild (CISA KEV)
- Used in ransomware campaigns
- CISA SSVC: automatable with total technical impact
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 90.1% (top 1%) |
| CISA exploited list | Yes, fix due 2026-03-12, used in ransomware |
| Weakness | CWE-502 |
| Published | 2025-09-23 |
| Last modified | 2026-10-11 |
Last updated 2026-10-11 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Exploited Added to the CISA Known Exploited Vulnerabilities list
- Deadline CISA due date for US federal agencies to patch
- Updated Record last modified
Exact fixes by distribution
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- GitHub PoC: rxerium/CVE-2025-26399 (2 stars)
- GitHub PoC: h4xnz/CVE-2025-26399-Exploit
- Nuclei scan template: SolarWinds Web Help Desk < 12.8.7 - AjaxProxy Deserialization RCE
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2025-26399?
web help desk: upgrade to newer than 12.8.6. Exact commands for each OS are on this page.
Is CVE-2025-26399 being exploited?
Yes. CVE-2025-26399 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.
What does CVE-2025-26399 affect?
CVE-2025-26399 affects web help desk. Severity is critical (CVSS 9.8). 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
How urgent is CVE-2025-26399?
Priority 97/100. Critical severity; EPSS top 1%: very likely to be exploited; Exploited in the wild (CISA KEV); Used in ransomware campaigns; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action
Related CVEs
- CVE-2026-28323 CRITICAL 9.8 UPGRADE SolarWinds Web Help Desk is found to be affected by a SAML authentication bypass vulnerability
- CVE-2026-28299 HIGH 8.2 UPGRADE SolarWinds Web Help Desk is found to be affected by a denial-of-service vulnerability, which when exploited, c
- CVE-2025-40554 CRITICAL 9.8 UPGRADE SolarWinds Web Help Desk was found to be susceptible to an authentication bypass vulnerability that, if exploi
- CVE-2025-40553 CRITICAL 9.8 UPGRADE SolarWinds Web Help Desk was found to be susceptible to an untrusted data deserialization vulnerability that c
- CVE-2025-40552 CRITICAL 9.8 UPGRADE SolarWinds Web Help Desk was found to be susceptible to an authentication bypass vulnerability that if exploit