What is the CVSS score of CVE-2026-23604?

CVE-2026-23604 has a CVSS 3.1 base score of 5.4 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.0%.

Which versions of Mailessentials are affected by CVE-2026-23604?

CVE-2026-23604 presents moderate security risk, a cross-site scripting vulnerability rated CVSS 5.4. Attackers could inject scripts to steal sessions or perform actions as authenticated users.

How to fix or mitigate CVE-2026-23604?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Mailessentials CVE-2026-23604

MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2026-02-19 disclosure@vulncheck.com

XSS Mailessentials

5.4

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

5.4 MEDIUM

AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:03 vuln.today

CVE Published

Feb 19, 2026 - 18:24 nvd

MEDIUM 5.4

DescriptionCVE.org

GFI 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.

AnalysisAI

Stored cross-site scripting in GFI MailEssentials AI versions before 22.4 allows authenticated users to inject malicious JavaScript into the Keyword Filtering rule creation interface, which executes when administrators view the management console. An attacker with valid credentials can compromise other users' sessions and perform unauthorized actions within the MailEssentials application. …

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Vulnerability AssessmentAI

Risk Assessment	CVSS 5.4 (MEDIUM). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario	An attacker (requires authentication) could exploit this vulnerability to compromise the affected system.
Remediation	Monitor vendor advisories for a patch. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. …

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CVE-2026-23604 vulnerability details – vuln.today

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