CVE-2021-41750: A cross-site scripting (XSS) vulnerability in the SEOmatic plugin 3.4.10 for Craft CMS 3 allows remote attacke

Routine

MEDIUM 6.1DOWNGRADE

CVE-2021-41750 is a medium-severity flaw (CVSS 6.1) affecting seomatic. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A cross-site scripting (XSS) vulnerability in the SEOmatic plugin 3.4.10 for Craft CMS 3 allows remote attackers to inject arbitrary web script via a GET to /index.php?action=seomatic/file/seo-file-link with url parameter containing the base64 encoded URL of a malicious web page / file and fileName parameter containing an arbitrary filename with the intended content-type to be rendered in the user's browser as the extension.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.1% (top 34%)
CISA exploited list	No
Weakness	CWE-79
Published	2022-06-12
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: nystudio107

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-06-12 12:15 UTCPublished CVE record published
2026-06-17 04:08 UTCUpdated Record last modified

nystudio107 seomatic DOWNGRADE

Affected: 3.4.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.4.10

1. Check installed version

apt-cache policy seomatic || rpm -q seomatic || seomatic --version

2. No fixed release: DOWNGRADE to a release before 3.4.10 (Debian / Ubuntu)

apt-cache madison seomatic sudo apt install seomatic=<VERSION_BEFORE_3.4.10> sudo apt-mark hold seomatic

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list seomatic sudo dnf downgrade seomatic-<VERSION_BEFORE_3.4.10> sudo dnf versionlock add seomatic

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-41750?

seomatic: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-41750 being exploited?

CVE-2021-41750 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-41750 affect?

CVE-2021-41750 affects seomatic. Severity is medium (CVSS 6.1). A cross-site scripting (XSS) vulnerability in the SEOmatic plugin 3.4.10 for Craft CMS 3 allows remote attackers to inject arbitrary web script via a GET to /index.php?action=seomatic/file/seo-file-link with url parameter containing the bas

How urgent is CVE-2021-41750?

Priority 38/100. No elevated risk signals yet.

Software pages

PHP vulnerabilities

Related CVEs

CVE-2021-44618 CRITICAL 9.8 DOWNGRADE A Server-side Template Injection (SSTI) vulnerability exists in Nystudio107 Seomatic 3.4.12 in src/helpers/Url
CVE-2021-41749 CRITICAL 9.8 UPGRADE In the SEOmatic plugin up to 3.4.11 for Craft CMS 3, it is possible for unauthenticated attackers to perform a
CVE-2020-12790 HIGH 7.5 UPGRADE In the SEOmatic plugin before 3.2.49 for Craft CMS, helpers/DynamicMeta.php does not properly sanitize the URL

References

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