CVE-2025-26399: SolarWinds Web Help Desk Deserialization of Untrusted Data Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 167 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 90.1%
EPSS score, percentile 99.8 of all scored records
- How severe?
- 9.8 Critical
CVSS v3.1 base score, given by the CNA
- What should I do?
CISA deadline . Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- 12.8.7 and below
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
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 due date for this action: .
Solution (from the CVE record)
SolarWinds recommends customers to upgrade to Web Help Desk version 12.8.7 HF1 as soon as is practical.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- https://www.solarwinds.com/trust-center/security-advisories/cve-2025-26399
- https://documentation.solarwinds.com/en/success_center/whd/content/release_notes/whd_12-8-7-hotfix-1_release_notes.htm
- https://nvd.nist.gov/vuln/detail/CVE-2025-26399
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | 12.8.7 and below |
Versions not listed are: unaffected.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
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.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2025-26399 to its Known Exploited Vulnerabilities (KEV) catalog on 9 Mar 2026.
- CISA marks it as known to be used in ransomware campaigns.
- The due date CISA sets for the required action is 12 Mar 2026.
- The CVE record was published on 23 Sep 2025, 167 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 90.1% (percentile 99.8), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
SolarWinds Web Help Desk Deserialization of Untrusted Data Privilege Escalation Vulnerability
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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
- CWE-502: Deserialization of Untrusted Data
Attack patterns (CAPEC)
- CAPEC-248: Untrusted Execution Flow
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |
References
More exploited SolarWinds vulnerabilities
- CVE-2026-28318: SolarWinds Serv-U Uncontrolled Resource Consumption Vulnerability
- CVE-2025-40536: SolarWinds Web Help Desk Security Control Bypass Vulnerability
- CVE-2025-40551: SolarWinds Web Help Desk Deserialization of Untrusted Data Vulnerability
- CVE-2024-28987: SolarWinds Web Help Desk Hardcoded Credential Vulnerability
- CVE-2024-28986: SolarWinds Web Help Desk Deserialization of Untrusted Data Vulnerability
- CVE-2024-28995: SolarWinds Serv-U Path Traversal Vulnerability