Description

MDC is a tool to take regular Markdown and write documents interacting deeply with a Vue component. In affected versions unsafe parsing logic of the URL from markdown can lead to arbitrary JavaScript code due to a bypass to the existing guards around the `javascript:` protocol scheme in the URL. The parsing logic implement in `props.ts` maintains a deny-list approach to filtering potential malicious payload. It does so by matching protocol schemes like `javascript:` and others. These security guards can be bypassed by an adversarial that provides JavaScript URLs with HTML entities encoded via hex string. Users who consume this library and perform markdown parsing from unvalidated sources could result in rendering vulnerable XSS anchor links. This vulnerability has been addressed in version 0.13.3 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

Classification

CVE ID: CVE-2025-24981

CVSS Base Severity: CRITICAL

CVSS Base Score: 9.3

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

Affected Products

Vendor: nuxt-modules

Product: mdc

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.05% (probability of being exploited)

EPSS Percentile: 18.35% (scored less or equal to compared to others)

EPSS Date: 2025-03-07 (when was this score calculated)

References

https://github.com/nuxt-modules/mdc/security/advisories/GHSA-j82m-pc2v-2484
https://github.com/nuxt-modules/mdc/commit/99097738b5561639e9bf247c55d8103236618bf3
https://github.com/nuxt-modules/mdc/blob/main/src/runtime/parser/utils/props.ts#L16

Timeline