What is the CVSS score of CVE-2023-6621?

CVE-2023-6621 has a CVSS 3.1 base score of 6.1 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.1%.

Which versions of Post Smtp are affected by CVE-2023-6621?

Organizations using before 2.8.7 does not sanitise and escape the msg parameter should be aware of moderate risk from CVE-2023-6621, a cross-site scripting vulnerability rated CVSS 6.1.

Is there a public PoC exploit available for CVE-2023-6621?

Yes, a public proof-of-concept exploit is available for CVE-2023-6621. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2023-6621?

Within 30 days: Identify affected systems running before 2.8.7 does not sanitise and escape the msg parameter and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Post Smtp CVE-2023-6621

MEDIUM

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

2024-01-03 contact@wpscan.com

WordPress XSS Post Smtp Wpexperts

6.1

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

6.1 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:33 vuln.today

PoC Detected

Jun 18, 2025 - 16:15 vuln.today

Public exploit code

CVE Published

Jan 03, 2024 - 09:15 nvd

MEDIUM 6.1

DescriptionCVE.org

AnalysisAI

The POST SMTP WordPress plugin before 2.8.7 does not sanitise and escape the msg parameter before outputting it back in the page, leading to a Reflected Cross-Site Scripting which could be used. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. The POST SMTP WordPress plugin before 2.8.7 does not sanitise and escape the msg parameter before outputting it back in the page, leading to a Reflected Cross-Site Scripting which could be used against high privilege users such as admin. Affected products include: Wpexperts Post Smtp. Version information: before 2.8.7.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.