What is CVE-2021-41749?

CVE-2021-41749 is a critical-severity vulnerability in Nystudio107 Seomatic, classified under Code Injection. CVSS score: 9.8/10. Published 2022-06-12.

How severe is CVE-2021-41749?

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

RCE in Nystudio107 Seomatic

CVE-2021-41749

In the SEOmatic plugin up to 3.4.11 for Craft CMS 3, it is possible for unauthenticated attackers to perform a Server-Side Template Injection, allowing for remote code execution.

Vulnerability class: RCE (Remote Code Execution)

Published 2022-06-12 · 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: 0.181 (97.1th percentile), scored 2026-10-03.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 97.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.181 · newest: 0.181 · change: 0.000

Affected products

Nystudio107 Seomatic

Weakness classification (CWE)

CWE-94 — Code Injection

References

github.com/nystudio107/craft-seomatic/blob/develop/CHANGELOG.md (Third Party Advisory, Release Notes)
github.com/nystudio107/craft-seomatic/commit/3fee7d50147cdf3f999cfc1e04cbc3fb3d… (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-41749?: CVE-2021-41749 is a critical-severity vulnerability in Nystudio107 Seomatic, classified under Code Injection. CVSS score: 9.8/10. Published 2022-06-12.
How severe is CVE-2021-41749?: Critical severity. CVSS v3 base score is 9.8 out of 10.