CVE-2026-23604
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 · uneditedGFI MailEssentials AI versions prior to 22.4 contain a stored cross-site scripting vulnerability in the Keyword Filtering rule creation workflow. An authenticated user can supply HTML/JavaScript in the ctl00$ContentPlaceHolder1$pv1$TXB_RuleName parameter to /MailEssentials/pages/MailSecurity/contentchecking.aspx, which is stored and later rendered in the management interface, allowing script execution in the context of a logged-in user.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceGFI MailEssentials AI versions prior to 22.4 contain a stored cross-site scripting vulnerability in the Keyword Filtering rule creation workflow. An authenticated attacker can inject malicious HTML/JavaScript into the ctl00$ContentPlaceHolder1$pv1$TXB_RuleName parameter on the contentchecking.aspx page, which persists and executes in the browsers of other administrative users viewing the management interface.
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< 22.4CVSS 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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Identify GFI MailEssentials installationCheck for GFI MailEssentials in installed programs (Windows Control Panel > Programs and Features) or look for installation directory at C:\Program Files\GFI\MailEssentials or C:\Program Files (x86)\GFI\MailEssentialsAffected if GFI MailEssentials is installed and version is below 22.4
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Confirm installed version numberLocate the version information in the installation directory, typically in an About or version file, or check the registry under HKEY_LOCAL_MACHINE\SOFTWARE\GFI\MailEssentialsAffected if Version is lower than 22.4 (e.g., 22.3, 22.2, earlier releases)
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Verify access to Keyword Filtering rulesAccess the web management interface and navigate to the Email Protection > Content Checking section, or directly access contentchecking.aspxAffected if User has administrative access to the content checking/keyword filtering configuration page
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Inspect existing keyword filtering rulesIn the management interface, list all configured Keyword Filtering rules and examine the RuleName field for each rule for suspicious HTML or JavaScript characters such as <script>, javascript:, onerror=, or encoded payloadsAffected if Any rule exists with RuleName containing HTML/JavaScript code that did not originate from the administrator
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Check audit logs for rule creationReview GFI MailEssentials logs for recent modifications to keyword filtering rules, looking for entries showing rule creation with unexpected characters in the rule nameAffected if Logs show rule creation activity that does not match expected administrative actions
You are affected if GFI MailEssentials AI version is below 22.4 and you have administrative access to the Keyword Filtering rule configuration in the management interface.
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 · scoped22.4
Implement strict input validation and proper output encoding for the RuleName parameter in the keyword filtering rule creation workflow, and deploy Content Security Policy headers to mitigate XSS execution.
22.4
- Upgrade GFI MailEssentials to version 22.4 or later
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-23604 — 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-2026-23604 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