What is CVE-2023-6621?

CVE-2023-6621 is a medium-severity vulnerability in Wpexperts Post Smtp, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2024-01-03.

How severe is CVE-2023-6621?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Is CVE-2023-6621 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

XSS in Wpexperts Post Smtp

CVE-2023-6621

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.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2024-01-03 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (32.0th percentile), scored 2026-10-03.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 32.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Wpexperts Post Smtp
Post Smtp — versions 0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

fkie-cad/nvd-json-data-feeds

References

wpscan.com/vulnerability/b49ca336-5bc2-4d72-a9a5-b8c020057928 (Exploit, technical-description, Third Party Advisory, exploit, vdb-entry)

Frequently asked questions

What is CVE-2023-6621?: CVE-2023-6621 is a medium-severity vulnerability in Wpexperts Post Smtp, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2024-01-03.
How severe is CVE-2023-6621?: Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2023-6621 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.