# CVE-2026-28309 — SolarWinds Serv-U

> As of 2026-07-24, CVE-2026-28309 is a CRITICAL-severity vulnerability in SolarWinds Serv-U, CVSS v3.1 9.1, EPSS 0.4% (40.5th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-28309, most recently “SolarWinds Serv-U 2026.3 Patches 16 Vulnerabilities (CVE-2026-28302 to CVE-2026-28321) Including Root RCE, IDOR-Chained Privilege Escalation, and Broken Access Control”.

**Last updated:** 2026-07-24

## What is CVE-2026-28309?

SolarWinds Serv-U is affected by a broken access control vulnerability that allows a domain administrator to create system administrator accounts. The impact is lower in Windows deployments.

The record classifies CVE-2026-28309 under weakness class [CWE-862](https://intel.threadlinqs.com/cwe/CWE-862). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs high-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 99 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 9.1 — CRITICAL (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H`)
- **EPSS (FIRST):** 0.4% probability of exploitation in the next 30 days, higher than 40.5% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 6.2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-21, last modified 2026-07-24

## Is CVE-2026-28309 being exploited?

It currently carries a trending score of 25 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [SolarWinds](https://intel.threadlinqs.com/vendors/solarwinds): Serv-U

## How to fix CVE-2026-28309

No vendor patch reference has been recorded for CVE-2026-28309 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-28309

1 tracked threat in the Threadlinqs corpus references CVE-2026-28309, either in the campaign’s CVE list or as an indicator on the campaign record.

- [SolarWinds Serv-U 2026.3 Patches 16 Vulnerabilities (CVE-2026-28302 to CVE-2026-28321) Including Root RCE, IDOR-Chained Privilege Escalation, and Broken Access Control](https://intel.threadlinqs.com/threat/TL-2026-1625) — CRITICAL · 2026-07-22

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-10-10.

**Vendor advisory and patch**

- [https — vendor advisory](https://https//www.solarwinds.com/trust-center/security-advisories/CVE-2026-28309)
- [documentation.solarwinds.com — release notes](https://documentation.solarwinds.com/en/success_center/servu/content/release_notes/servu_2026-3_release_notes.htm)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-28309
Full detection coverage and IOCs for threats exploiting CVE-2026-28309 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp