What is CVE-2018-16979?

CVE-2018-16979 is a medium-severity vulnerability in Monstra, classified under HTTP Response Splitting. CVSS score: 6.1/10. Published 2018-09-12.

How severe is CVE-2018-16979?

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

Is CVE-2018-16979 known to be exploited?

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

Vulnerability in Monstra

CVE-2018-16979

Monstra CMS V3.0.4 allows HTTP header injection in the plugins/captcha/crypt/cryptographp.php cfg parameter, a related issue to CVE-2012-2943.

Published 2018-09-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.030 (87.0th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 87th percentile — 87.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.030 · newest: 0.030 · change: 0.000

Affected products

Monstra — versions 3.0.4

Weakness classification (CWE)

CWE-113 — HTTP Response Splitting

Public proof-of-concept exploits

ARPSyndicate/kenzer-templates

References

github.com/howchen/howchen/issues/4 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2018-16979?: CVE-2018-16979 is a medium-severity vulnerability in Monstra, classified under HTTP Response Splitting. CVSS score: 6.1/10. Published 2018-09-12.
How severe is CVE-2018-16979?: Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2018-16979 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.