What is GHSA-q3jf-9wv7-p29w?

GHSA-q3jf-9wv7-p29w is a security advisory published by GitHub Security Advisories with Medium severity. justhtml versions before 1.13.0 contain a cross-site scripting vulnerability in the to_markdown()...

Which CVE IDs does GHSA-q3jf-9wv7-p29w cover?

GHSA-q3jf-9wv7-p29w covers the following CVE IDs: CVE-2026-5389. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of GHSA-q3jf-9wv7-p29w?

GHSA-q3jf-9wv7-p29w has a CVSS v3 base score of 6.1, published by GitHub Security Advisories.

GHSA-q3jf-9wv7-p29wMediumCVSS 6.1

justhtml versions before 1.13.0 contain a cross-site scripting vulnerability in the to_markdown()...

Vendor

GitHub Security Advisories

Published

August 23, 2026

Last Modified

August 23, 2026

🔗 CVE IDs covered (1)

CVE-2026-5389 →

📋 Description

justhtml versions before 1.13.0 contain a cross-site scripting vulnerability in the to_markdown() function when serializing attacker-controlled pre content. Attackers can place backticks inside sanitized pre elements to break out of fixed-length code fences, allowing raw HTML to execute when the generated Markdown is rendered by CommonMark or GFM-style renderers.

🔗 References (4)

https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-5vp3-3cg6-2rq3
https://nvd.nist.gov/vuln/detail/CVE-2026-5389
https://www.vulncheck.com/advisories/justhtml-before-xss-via-code-fence-breakout
https://github.com/advisories/GHSA-q3jf-9wv7-p29w