What is CVE-2017-18437?

CVE-2017-18437 is a medium-severity vulnerability in Cpanel, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 4.4/10. Published 2019-08-02.

How severe is CVE-2017-18437?

Medium severity. CVSS v3 base score is 4.4 out of 10.

Vulnerability in Cpanel

CVE-2017-18437

cPanel before 64.0.21 allows a Webmail account to execute code via forwarders (SEC-240).

Published 2019-08-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.005 (37.3th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 37.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Cpanel

Weakness classification (CWE)

CWE-74 — Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection)

References

documentation.cpanel.net/display/CL/64+Change+Log (Release Notes, Vendor Advisory)
news.cpanel.com/cpanel-tsr-2017-0003-full-disclosure/ (Vendor Advisory)

Frequently asked questions

What is CVE-2017-18437?: CVE-2017-18437 is a medium-severity vulnerability in Cpanel, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 4.4/10. Published 2019-08-02.
How severe is CVE-2017-18437?: Medium severity. CVSS v3 base score is 4.4 out of 10.