How severe is CVE-2021-44618?

CVE-2021-44618 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-44618 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-44618?

CVE-2021-44618 affects Nystudio107 Seomatic. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-44618?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-44618 published?

CVE-2021-44618 was published on 2022-03-11 and last updated on 2026-06-17.

CVE-2021-44618

CVE-2021-44618 is a critical-severity vulnerability in Nystudio107 Seomatic with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-94.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-94
Affected product: Nystudio107 Seomatic
Published: 2022-03-11
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is 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.
How severe is CVE-2021-44618?: CVE-2021-44618 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-44618 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-44618?: CVE-2021-44618 affects Nystudio107 Seomatic. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-44618?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-44618 published?: CVE-2021-44618 was published on 2022-03-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:nystudio107:seomatic:3.4.12:*:*:*:*:craft_cms:*:*

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