CVE-2026-50591
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 · uneditedIn Znuny LTS before 6.5.21 and Znuny before 7.3.3, XSS can occur via stored user preferences.
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 · high confidenceIn Znuny LTS before 6.5.21 and Znuny before 7.3.3, stored XSS can occur via user preferences. The application fails to properly sanitize user-provided preference data before storing it, allowing malicious scripts to be executed when other users view these preferences.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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 Znuny installation existsCheck for Znuny web application files in the web server document root, typically under /opt/znuny or the web server's application directory. Look for the typical Znuny directory structure containing Kernel, var, and scripts folders.Affected if Znuny software is not found on the system
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Identify the installed Znuny versionCheck the version file in the Znuny installation, commonly found at /opt/znuny/Kernel/VERSION or /opt/znuny/scripts/znuny-version.txt. Alternatively, access the Znuny admin panel and navigate to System Administration > System Overview to view the version information.Affected if Unable to determine the Znuny version from the system
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Compare version against fixed releasesCompare your installed version to the known fixed versions: Znuny LTS 6.5.21 and Znuny 7.3.3. For LTS 6.x versions, any version below 6.5.21 is affected. For version 7.x, any version below 7.3.3 is affected.Affected if Znuny LTS version is below 6.5.21 OR Znuny version 7.x is below 7.3.3
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Verify user preferences functionality is accessibleLog into Znuny as an authenticated user and navigate to the user preferences or user settings area, typically found under 'Preferences' or 'User Profile' in the web interface. Confirm the functionality is available and not disabled by administrator configuration.Affected if User preferences functionality is enabled and accessible to authenticated users
The environment is affected if Znuny is installed with a version below 6.5.21 (LTS) or below 7.3.3, and the user preferences functionality is accessible to authenticated users.
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.
dbcve · scopedUpgrade to Znuny LTS 6.5.21 or Znuny 7.3.3 or later, which contains the fix for this stored XSS vulnerability in user preferences.
Znuny LTS 6.5.21+ or Znuny 7.3.3+
- Identify the current Znuny installation version (LTS or regular)
- If running Znuny LTS, upgrade to version 6.5.21 or later
- If running Znuny, upgrade to version 7.3.3 or later
- After upgrading, clear browser cache and test that stored user preferences no longer accept malicious scripts
- Verify the upgrade by checking the About page shows the new version number
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation8.0 h
- Testing6.0 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 $4,960.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-50591 — 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-2026-50591 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
- No spam, self-promotion, credentials, or personal data