CVE-2025-24981: Parsed HTML anchor links in Markdown provided to parseMarkdown can result in XSS in @nuxtjs/mdc

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.7%, percentile 52: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 52% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes @nuxtjs/mdc (npm) <= 0.13.2, fixed in 0.13.3. Check your lockfile, including transitive dependencies.

What it is

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.

From the GitHub advisory

Summary An 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.

Details

The parsing logic implement at https://github.com/nuxt-modules/mdc/blob/main/src/runtime/parser/utils/props.ts#L16 maintains a deny-list approach to filtering potential malicious payload. It does so by matching protocol schemes like javascript: and others.

Specifically, this is the code from the mdc library's parser that is not secure enough:

These security guards can be bypassed by an adversarial that provides JavaScript URLs with HTML entities encoded via hex string.

Weakness type: CWE-79.

Product: @nuxtjs/mdc (npm) · Assigned by: GitHub_M · Published: 2025-02-06

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable yes, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 0.68% probability of exploitation activity in the next 30 days; percentile 52.

Timeline

• 2025-02-06 — CVE record published by GitHub_M
• 2025-02-06 — GitHub-reviewed advisory GHSA-j82m-pc2v-2484 published (critical)
• 2025-02-12 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-j82m-pc2v-2484 github.com
2. CVE.org record CVE-2025-24981 cve.org
3. NVD entry CVE-2025-24981 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com

Critical npm advisories · Today’s Security Digest