CVE-2026-63671 — HIGH (8.1)

Vulnerability Description

MDC is a tool to take regular Markdown and write documents interacting deeply with a Vue component. Prior to 0.22.1, @nuxtjs/mdc uses parseMarkdown with allowDangerousHtml enabled by default and relies on validateProps, validateProp, and unsafeLinkPrefix to remove executable URLs from untrusted Markdown. validateProp checks only attributes named href or src, allowing an SVG xlink:href value represented as xLinkHref to retain a javascript: URL that executes in the page origin when selected. The data:text/html denylist entries are also compared against url.protocol, which is only data:, so an iframe src containing data:text/html survives sanitization and executes in an opaque origin when loaded. Plain href javascript: URLs, srcdoc, object, script, and base elements are already blocked, making these two paths specific sibling gaps in the sanitizer. This issue is fixed in version 0.22.1.

CVSS Score

8.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

NONE

Related Weaknesses (CWE)

CWE-79 CWE-184

References

FAQ

What is CVE-2026-63671?

CVE-2026-63671 is a vulnerability with a CVSS score of 8.1 (HIGH). MDC is a tool to take regular Markdown and write documents interacting deeply with a Vue component. Prior to 0.22.1, @nuxtjs/mdc uses parseMarkdown with allowDangerousHtml enabled by default and relie...

How severe is CVE-2026-63671?

CVE-2026-63671 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-63671?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.