What is CVE-2021-44618?

CVE-2021-44618 is a critical-severity vulnerability in Nystudio107 Seomatic, classified under Code Injection. CVSS score: 9.8/10. Published 2022-03-11.

How severe is CVE-2021-44618?

Critical severity. CVSS v3 base score is 9.8 out of 10.

RCE in Nystudio107 Seomatic

CVE-2021-44618

A Server-side Template Injection (SSTI) vulnerability exists in Nystudio107 Seomatic 3.4.12 in src/helpers/UrlHelper.php via the host header.

Vulnerability class: RCE (Remote Code Execution)

Published 2022-03-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.014 (71.4th percentile), scored 2026-10-03.

Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 71.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000

Affected products

Nystudio107 Seomatic — versions 3.4.12

Weakness classification (CWE)

CWE-94 — Code Injection

References

github.com/nystudio107/craft-seomatic/releases/tag/3.4.12 (Third Party Advisory, Release Notes)
github.com/nystudio107/craft-seomatic/commit/0c5c0c0e0cb61000d12ec55ebf174745a5… (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-44618?: CVE-2021-44618 is a critical-severity vulnerability in Nystudio107 Seomatic, classified under Code Injection. CVSS score: 9.8/10. Published 2022-03-11.
How severe is CVE-2021-44618?: Critical severity. CVSS v3 base score is 9.8 out of 10.