CVE-2026-57530: XSS (CVSS 5.4)

Description

Milkdown before 7.21.3 contains a stored cross-site scripting vulnerability in the @milkdown/preset-commonmark and @milkdown/components packages that allows attackers with document write access to execute arbitrary JavaScript in the browser context of any user who opens the document or clicks a rendered link. The parseMarkdown runner stores raw URL values from the remark AST as href mark attributes without URL scheme validation, and the ineffective DOMPurify.sanitize call in edit-view.ts treats the bare URL string as a text node and returns it unchanged, allowing javascript: payloads to pass through the link-tooltip preview component and read-only mode anchor elements unmodified.

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CVSS v3.1 Score

5.4

MEDIUM

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

EPSS — Exploit Prediction

0.0018

Probability of exploitation

0.08%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://github.com/Milkdown/milkdown/commit/db1ae721854a0ab2f188b83cf8695702966640f1 https://github.com/Milkdown/milkdown/pull/2410 https://github.com/Milkdown/milkdown/releases/tag/v7.21.3 https://www.npmjs.com/package/@milkdown/components https://www.npmjs.com/package/@milkdown/preset-commonmark https://www.vulncheck.com/advisories/milkdown-stored-xss-via-javascript-url-in-link-href

Frequently Asked Questions

What is CVE-2026-57530? +

Milkdown before 7.21.3 contains a stored cross-site scripting vulnerability in the @milkdown/preset-commonmark and @milkdown/components packages that allows attackers with document write access to execute arbitrary JavaScript in the browser context of any user who opens the document or clicks a rendered link. The parseMarkdown runner stores raw URL values from the remark AST as href mark attributes without URL scheme validation, and the ineffective DOMPurify.sanitize call in edit-view.ts treats the bare URL string as a text node and returns it unchanged, allowing javascript: payloads to pass through the link-tooltip preview component and read-only mode anchor elements unmodified. It has a CVSS v3.1 base score of 5.4 (MEDIUM).

How severe is CVE-2026-57530? +

CVE-2026-57530 has a CVSS v3.1 score of 5.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0018, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-57530? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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