CVE-2021-44618

CRITICALNVD 9.89.8—

9.8

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

CVSS v3: 9.8
EG Score: 9.8(medium)
EPSS: 66.8%
KEV: Not listed

Published

March 11, 2022

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated May 26, 2026

Patch available. Sources: github_commit, github_release.

github_release Patch Available

Version 3.4.12

Patch available: nystudio107/craft-seomatic 3.4.12

https://github.com/nystudio107/craft-seomatic/releases/tag/3.4.12

github_commit Patch Available

commit 0c5c0c0e0cb6 (nystudio107/craft-seomatic)

Patch available: nystudio107/craft-seomatic 3.5.14 (contains commit 0c5c0c0e0cb6)

https://github.com/nystudio107/craft-seomatic/commit/0c5c0c0e0cb61000d12ec55ebf174745a5bf6469

Affected Packages

(1 across 1 ecosystem)

Packagist(1)

Package	Vulnerable range	Fixed in	Dependents
nystudio107/craft-seomatic	3.0.0 ... 3.4.9 (211 versions)	3.4.12	—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-94Improper Control of Generation of Code (Code Injection)

Data Freshness Timeline

(refreshed 11× in last 7d / 19× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 01:47 UTCEG score recompute

Frequently asked(5)

What is CVE-2021-44618?

CVE-2021-44618 is a critical vulnerability published on March 11, 2022. A Server-side Template Injection (SSTI) vulnerability exists in Nystudio107 Seomatic 3.4.12 in src/helpers/UrlHelper.php via the host header.

When was CVE-2021-44618 disclosed?

CVE-2021-44618 was first published in the National Vulnerability Database on March 11, 2022, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-44618 actively exploited?

CVE-2021-44618 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 66.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-44618?

CVE-2021-44618 has a CVSS v3 base score of 9.8 (NVD).

How do I remediate CVE-2021-44618?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-44618, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-44618

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CVE-2021-44618

📅 Published

🔄 Last Modified

📋 Advisory Details (2)