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CVE Record

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

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-41750 is a reported cross-site scripting issue in SEOmatic 3.4.10 for Craft CMS 3. A remote attacker could cause a victim’s browser to render attacker-controlled script through a plugin file-link action. Business risk is mainly user/session compromise, phishing, or brand abuse on affected public sites.

Executive priority

Treat this as a targeted web application hygiene issue, not a confirmed emergency. Prioritize internet-facing Craft CMS sites using SEOmatic 3.4.10, because XSS can affect customers, administrators, or authenticated sessions even without server compromise.

Technical view

The CVE describes XSS through GET requests to /index.php?action=seomatic/file/seo-file-link using a base64-encoded url parameter and a fileName parameter influencing rendered content type. The record names SEOmatic 3.4.10 for Craft CMS 3, but provides no CVSS score, CWE, or affected CPE data.

Likely exposure

Exposure appears limited to Craft CMS 3 deployments running the SEOmatic plugin version 3.4.10. Public-facing sites are the primary concern because the vulnerable route is web-accessible. The source bundle does not identify other affected versions or platforms.

Exploitation context

The source bundle does not show CISA KEV listing or any cited evidence of active exploitation. The described attack is remotely reachable and browser-executed, but exploitation would generally depend on getting a user to visit or interact with a crafted URL.

Researcher notes

Evidence is sparse: the CVE description is specific, but severity, CWE, CPEs, and fixed version details are absent from the provided bundle. The GitHub changelog and commits are the key vendor artifacts to inspect before asserting patch status or affected-version range.

Mitigation direction

  • Inventory Craft CMS 3 sites for SEOmatic plugin version 3.4.10.
  • Check the vendor changelog and referenced commits for the corrected release.
  • Upgrade SEOmatic according to vendor guidance when the fixed version is confirmed.
  • If upgrade guidance is unclear, consider disabling SEOmatic on exposed sites temporarily.
  • Monitor web logs for requests to the SEOmatic file-link action.

Validation and detection

  • Confirm whether Craft CMS 3 and SEOmatic 3.4.10 are installed.
  • Review routes and logs for the seomatic/file/seo-file-link action.
  • Check plugin release history against the referenced vendor changelog.
  • Validate remediation by confirming the vulnerable version is no longer present.
  • Avoid live payload testing unless approved and safely scoped.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2021-41750 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.