# CVE-2025-26399: SolarWinds Web Help Desk Deserialization of Untrusted Data

> Unauthenticated attackers can achieve remote code execution and privilege escalation via deserialization in SolarWinds Web Help Desk.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 9 Mar 2026 (CISA KEV), used in ransomware
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Sep 2025
- **Updated:** 4 Aug 2026
- **Also known as:** GHSA-vfrj-f292-3f24

## What is CVE-2025-26399?

CVE-2025-26399 is a critical unsafe deserialization vulnerability in SolarWinds Web Help Desk, published on 23 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2025-26399?

It affects 1 product.


Products: Solarwinds Web Help Desk.

## How do I fix CVE-2025-26399?

No fix has been published for CVE-2025-26399 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 12 Mar 2026.

## Is CVE-2025-26399 being exploited?

Yes. Attackers have exploited CVE-2025-26399 in the wild since at least 9 Mar 2026, including in ransomware campaigns.

Public exploit code:

- Detection for CVE-2025-26399 (github_poc): https://github.com/rxerium/CVE-2025-26399
- SolarWinds Web Help Desk < 12.8.7 - AjaxProxy Deserialization RCE (nuclei): http/cves/2025/CVE-2025-26399.yaml

## Other vulnerabilities in SolarWinds Web Help Desk

- [CVE-2025-40551](https://insights.sbomify.com/CVE-2025-40551/): SolarWinds Web Help Desk Deserialization of Untrusted Data (critical 9.8, exploited in the wild)
- [CVE-2024-28986](https://insights.sbomify.com/CVE-2024-28986/): SolarWinds Web Help Desk Deserialization of Untrusted Data (critical 9.8, exploited in the wild)
- [CVE-2024-28987](https://insights.sbomify.com/CVE-2024-28987/): SolarWinds Web Help Desk Hardcoded Credential (critical 9.1, exploited in the wild)
- [CVE-2025-40536](https://insights.sbomify.com/CVE-2025-40536/): SolarWinds Web Help Desk Security Control Bypass (high 8.1, exploited in the wild)
- [CVE-2026-28323](https://insights.sbomify.com/CVE-2026-28323/): SolarWinds Web Help Desk SAML Authentication Bypass Vulnerability (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-26399 and fix it if it is affected.

What it is: CVE-2025-26399 is a critical unsafe deserialization vulnerability in SolarWinds Web Help Desk, published on 23 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2025-26399 in the wild since at least 9 Mar 2026, including in ransomware campaigns.

Affected product: SolarWinds Web Help Desk. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-26399/ (Markdown: https://insights.sbomify.com/CVE-2025-26399/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-26399
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-26399
- OSV: https://osv.dev/vulnerability/CVE-2025-26399

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-26399/
Summaries are generated and may contain mistakes; the official description above is the record.