# SolarWinds Web Help Desk RCE via AjaxProxy deserialization

Published: 2026-06-09 · Severity: elevated
Canonical: https://vorant.io/reports/d750ff9f-29e7-58b4-af1c-d56b136a1ba1/solarwinds-web-help-desk-rce-via-ajaxproxy-deserialization

> Unauthenticated RCE in SolarWinds Web Help Desk 12.8.7 and earlier via AjaxProxy deserialization; patch immediately.

SolarWinds Web Help Desk versions 12.8.7 and all previous versions contain an unauthenticated remote code execution vulnerability in the AjaxProxy deserialization handler. This is a bypass of two prior patches (CVE-2024-28988 and CVE-2024-28986), tracked as CVE-2025-26399. An unauthenticated attacker can exploit this vulnerability to execute arbitrary code in the SYSTEM context, allowing full compromise including program installation, data manipulation, and account creation with administrative privileges. No active exploitation in the wild has been reported at the time of publication, but the flaw affects all deployed instances lacking a patch, making it a significant risk to any organization running SolarWinds Web Help Desk. The vulnerability requires no user interaction and is remotely exploitable via the public-facing application interface.

## Mentioned in this report

- Vulnerabilities: CVE-2024-28986 (KEV), CVE-2024-28988, CVE-2025-26399 (KEV)

## Detection guidance (public sample)

### SolarWinds Web Help Desk Java Process Spawning Shell or LOLBin

ATT&CK: T1059

Web Help Desk's Java/Tomcat process spawning cmd, PowerShell or common download and execution utilities, consistent with post-exploitation of an AjaxProxy deserialization RCE. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.

```yaml
title: SolarWinds Web Help Desk Java Process Spawning Shell or LOLBin
description: Detects the Web Help Desk Java service process spawning command interpreters
  or download/execution utilities. Successful exploitation of the AjaxProxy deserialization
  RCE (CVE-2025-26399) runs attacker code in the SYSTEM context of this process, so
  child shells are the visible result.
tags:
- attack.execution
- attack.t1059
- attack.initial-access
- attack.t1190
logsource:
  category: process_creation
  product: windows
detection:
  selection_parent:
    ParentImage|endswith:
    - \java.exe
    - \javaw.exe
    ParentImage|contains:
    - WebHelpDesk
    - Web Help Desk
  selection_child:
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \pwsh.exe
    - \wscript.exe
    - \cscript.exe
    - \mshta.exe
    - \certutil.exe
    - \bitsadmin.exe
    - \rundll32.exe
    - \regsvr32.exe
    - \curl.exe
  condition: selection_parent and selection_child
falsepositives:
- Administrators running custom maintenance or backup scripts launched from the Web
  Help Desk service
- Vendor upgrade or installer routines invoking cmd.exe from the bundled Java runtime
level: high
id: b479fb22-6e44-5dd7-b7a5-342f62c86eba
status: experimental
author: Vorant
references:
- https://www.cisecurity.org/advisory/a-vulnerability-in-solarwinds-web-help-desk-could-allow-for-remote-code-execution_2025-089
```

### Web Request to SolarWinds Web Help Desk AjaxProxy Endpoint

ATT&CK: T1190

HTTP POST requests to the Web Help Desk AjaxProxy handler, the deserialization entry point abused by CVE-2025-26399 and its predecessors. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.

```yaml
title: Web Request to SolarWinds Web Help Desk AjaxProxy Endpoint
description: Detects POST requests to a Web Help Desk URI containing AjaxProxy, the
  handler whose deserialization flaw allows unauthenticated RCE (CVE-2025-26399, bypass
  of CVE-2024-28988 and CVE-2024-28986). Needs context; legitimate UI traffic may
  hit related endpoints, so review sources, request size and subsequent process activity.
tags:
- attack.initial-access
- attack.t1190
logsource:
  category: webserver
detection:
  selection:
    cs-method: POST
    cs-uri-stem|contains: AjaxProxy
  condition: selection
falsepositives:
- Legitimate Web Help Desk UI use that calls AjaxProxy-based Ajax components
- Authorised vulnerability scanners probing the Web Help Desk instance
level: medium
id: 45935d7a-c33c-56ff-9042-15bcca6dd891
status: experimental
author: Vorant
references:
- https://www.cisecurity.org/advisory/a-vulnerability-in-solarwinds-web-help-desk-could-allow-for-remote-code-execution_2025-089
```

Behavioural rules are generated from public reporting — validate in your environment before deploying.

Source reporting: https://www.cisecurity.org/advisory/a-vulnerability-in-solarwinds-web-help-desk-could-allow-for-remote-code-execution_2025-089

---

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