# CVE-2026-28307: SolarWinds Serv-U privilege escalation in domain user groups

Source: https://junglewise.ai/threats/cve-2026-28307-solarwinds-serv-u-privilege-escalation-in-domain-user-groups  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-21. Updated: 2026-07-21  
License: CC BY 4.0 with a link back

CVE-2026-28307 · Severity: critical · CVSS 9.1 · Published 2026-07-21

SolarWinds Serv-U, a managed file transfer and FTP server, is affected by a security flaw that allows certain users to gain unauthorized administrative control. An attacker with existing high-level permissions could exploit this to elevate a standard domain user group into a full administrator group. This could lead to a complete takeover of the file transfer service and unauthorized access to sensitive data stored on the server.

Technologies: [SolarWinds Serv-U](https://junglewise.ai/threats/technologies/serv-u). Vendors: [SolarWinds](https://junglewise.ai/threats/vendors/solarwinds).

## Quick answers

**Is CVE-2026-28307 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-28307 being exploited in the wild.

**How severe is CVE-2026-28307?** Critical severity, with a CVSS score of 9.1, published 21 July 2026.

**Which products and versions are affected?** SolarWinds Serv-U 15.5.4 HF1 and below.

**Is there a fix for CVE-2026-28307?** A patch was published on 2026-07-21: Fixed in Serv-U 2026.3 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-28307 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-28307?** Check whether you run SolarWinds Serv-U at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A privilege escalation vulnerability exists in SolarWinds Serv-U due to improper access control (CWE-284). The flaw allows an attacker with high-privileged credentials to elevate a domain user group to an administrator group, potentially leading to a full compromise of the Serv-U instance. The attack vector is network-based and requires high privileges but no user interaction. While the vulnerability affects multiple platforms, the vendor notes that the impact is lower in Windows-based deployments. The issue is resolved in Serv-U version 2026.3.

## Affected products

- SolarWinds Serv-U 15.5.4 HF1 and below

## Timeline

- 2026-07-21: advisory: Initial advisory published by SolarWinds
- 2026-07-21: patched: Fixed in Serv-U 2026.3

## References

- [https://documentation.solarwinds.com/en/success_center/servu/content/release_notes/servu_2026-3_release_notes.htm](https://documentation.solarwinds.com/en/success_center/servu/content/release_notes/servu_2026-3_release_notes.htm)
- [https://www.solarwinds.com/trust-center/security-advisories/CVE-2026-28307](https://www.solarwinds.com/trust-center/security-advisories/CVE-2026-28307)

## Related threats

- [SolarWinds Serv-U broken access control privilege escalation](https://junglewise.ai/threats/cve-2026-28321-solarwinds-serv-u-broken-access-control-privilege-escalation)
- [SolarWinds Serv-U privilege escalation via IDOR](https://junglewise.ai/threats/cve-2026-28317-solarwinds-serv-u-privilege-escalation-via-idor)
- [SolarWinds Serv-U IDOR privilege escalation to root](https://junglewise.ai/threats/cve-2026-28316-solarwinds-serv-u-idor-privilege-escalation-to-root)
- [SolarWinds Serv-U stored XSS in administrator interface](https://junglewise.ai/threats/cve-2026-28315-solarwinds-serv-u-stored-xss-in-administrator-interface)
- [SolarWinds Serv-U account takeover via IDOR](https://junglewise.ai/threats/cve-2026-28314-solarwinds-serv-u-account-takeover-via-idor)