Security readout for executives and security teams
Plain-English summary
SolarWinds Web Help Desk 12.8.7 and earlier can let an unauthenticated attacker execute commands on the server. Successful compromise could expose help-desk data, alter systems, disrupt service, and provide a foothold into connected environments. This is a bypass of two earlier fixes, so prior remediation alone may not provide protection.
Executive priority
Treat this as an immediate remediation and threat-hunting priority. Assign accountable owners, protect exposed instances first, and require evidence of completed vendor remediation. Any affected system with suspicious activity should enter incident response rather than being considered resolved by patching alone.
Technical view
CVE-2025-26399 is a network-accessible AjaxProxy deserialization flaw classified as CWE-502. It requires no authentication, privileges, or user interaction and can produce host-level command execution. CVSS 3.1 rates it 9.8. The vulnerability bypasses CVE-2024-28988, itself a bypass of CVE-2024-28986.
Likely exposure
Organizations operating SolarWinds Web Help Desk 12.8.7 or earlier should presume exposure, especially where the service is internet-accessible or reachable from untrusted networks. The bundle does not identify particular configurations that eliminate risk. Inventory should also detect forgotten, externally published, or internally reachable instances.
Exploitation context
Active exploitation is supported by CISA KEV inclusion and the cited Microsoft advisory. The supplied evidence does not establish exploitation volume, targeted sectors, initial exploitation dates, or indicators of compromise. Because exploitation is unauthenticated and remotely reachable, exposed systems warrant urgent investigation.
Researcher notes
The title describes privilege escalation, while the supplied description specifies unauthenticated remote command execution; operational triage should follow the more severe documented behavior. This is the third vulnerability in a stated patch-bypass chain. The bundle provides no technical indicators, exploitation mechanics, or confirmation that every deployment mode is reachable.
Mitigation direction
- Review the SolarWinds advisory and 12.8.7 Hotfix 1 release notes immediately.
- Apply the vendor-documented remediation to every affected Web Help Desk instance.
- Restrict untrusted network access until vendor remediation is verified.
- Isolate suspected compromised servers and begin incident-response procedures.
- Rotate credentials or secrets accessible from confirmed compromised hosts.
Validation and detection
- Inventory all Web Help Desk instances and record versions, exposure, and owners.
- Confirm affected systems received the exact vendor-documented remediation.
- Verify internet-facing and untrusted-network access is restricted where remediation remains pending.
- Review Web Help Desk and host telemetry for unexplained commands, processes, files, or access.
- Reassess systems previously treated only for CVE-2024-28986 or CVE-2024-28988.
Public sources used
The source record changed after analysis: Material source record changed after analysis.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-502: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2025-26399 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9SolarWindsVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- Added to KEVCISA-ADP
CISA Known Exploited Vulnerabilities metadata lists this CVE as known exploited.
- ADP timelineCISA-ADP
CVE-2025-26399 added to CISA KEV
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-03-09T00:00:00.000Z: CVE-2025-26399 added to CISA KEV
Source materials
- CVE List V5 sourceCVE List V5
- https://www.solarwinds.com/trust-center/security-advisories/CVE-2025-26399CVE reference, SolarWinds
- https://documentation.solarwinds.com/en/success_center/whd/content/release_notes/whd_12-8-7-hotfix-1_release_notes.htmCVE reference, SolarWinds
- https://www.microsoft.com/en-us/security/blog/2026/02/06/active-exploitation-solarwinds-web-help-desk/CVE reference, CISA-ADP · third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-26399CVE reference, CISA-ADP · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Deserialization of Untrusted Data
Deserialization of Untrusted Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.