What is CVE-2018-18921?

CVE-2018-18921 is a medium-severity vulnerability in Phpservermonitor PHP Server Monitor, classified under Cross-Site Request Forgery (CSRF). CVSS score: 6.5/10. Published 2018-12-18.

How severe is CVE-2018-18921?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Is CVE-2018-18921 known to be exploited?

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

CSRF in Phpservermonitor PHP Server Monitor

CVE-2018-18921

PHP Server Monitor before 3.3.2 has CSRF, as demonstrated by a Delete action.

Vulnerability class: CSRF (Cross-Site Request Forgery)

Published 2018-12-18 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.006 (47.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Phpservermonitor PHP Server Monitor

Weakness classification (CWE)

CWE-352 — Cross-Site Request Forgery (CSRF)

Public proof-of-concept exploits

References

medium.com/bugbountywriteup/cve-2018-18921-php-server-monitor-3-3-1-cross-site-… (Exploit, Third Party Advisory)
github.com/phpservermon/phpservermon/issues/670 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2018-18921?: CVE-2018-18921 is a medium-severity vulnerability in Phpservermonitor PHP Server Monitor, classified under Cross-Site Request Forgery (CSRF). CVSS score: 6.5/10. Published 2018-12-18.
How severe is CVE-2018-18921?: Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2018-18921 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.