CVE-2026-28321
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedSolarWinds Serv-U is affected by a broken access control vulnerability that could allow arbitrary file read and write, which can then be used to escalate privileges and execute code as root. A domain administrator access is required, and the impact is lower in Windows installations.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceSolarWinds Serv-U contains a broken access control vulnerability that permits a domain administrator to perform arbitrary file read and write operations. This can be leveraged to escalate privileges and execute code as root. The impact is reduced on Windows installations.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 2026.3CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- High
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm Serv-U installationCheck for Serv-U installation by looking for the Serv-U service or executable. On Linux: systemctl status serv-u or ps aux | grep serv-u. On Windows: Check Services.msc for 'Serv-U' or look in C:\Program Files\Serv-UAffected if Serv-U is not installed or no Serv-U process is running - not affected
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Identify Serv-U versionOn Linux: /opt/Serv-U/Serv-U --version or check /opt/Serv-U/Serv-U-Version. On Windows: Right-click Serv-U.exe in the installation directory and select Properties > Details, or run Serv-U -V from the installation folderAffected if Installed version is any version prior to 2026.3 (e.g., 2026.2, 2026.1, earlier releases) - affected
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Check if domain administrator role existsLog into Serv-U administration console and navigate to Users or Domains section. Look for accounts with Domain Administrator privileges. Alternatively, check the Serv-U configuration files (servu.ini or domaincfg.xml) for user accounts with admin privilegesAffected if Domain administrator accounts are configured and active - potentially affected by privilege escalation
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Verify file system access permissionsIn Serv-U admin console, review the domain or user-level file access settings. Check if domain administrators have browse filesystem, read, or write permissions beyond their assigned home directories. Look for settings like 'Allow users to browse filesystem' or broad directory access rulesAffected if Domain administrators have broad filesystem access or can browse outside their home directory - vulnerable configuration present
If Serv-U is installed with a version lower than 2026.3 AND domain administrator accounts exist with broad filesystem access permissions, the environment is affected by this vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data2026.3
Restrict domain administrator access to Serv-U, apply available patches promptly, and minimize the attack surface by limiting Serv-U exposure to only necessary networks and users.
- Consultation4.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,544.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-28321 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-28321 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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