@nuxtjs/mdc: the URL sanitizer misses SVG xlink:href and data:text/html, allowing XSS from untrusted markdown at the default configuration
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 0.22.1
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: no
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- nuxt-content mdc
fixed in 0.22.1
- @nuxtjs/mdcnpm
fixed in 0.22.1