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.
Published: 2026-08-23
Score: 5.1 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Sun, 23 Aug 2026 14:00:00 +0000

Type Values Removed Values Added
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.
Title justhtml before 1.13.0 XSS via code fence breakout
Weaknesses CWE-80
References
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

cvssV4_0

{'score': 5.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N'}

Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-23T13:34:09.865Z

Reserved: 2026-04-01T21:14:36.435Z

Link: CVE-2026-5389

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-23T14:16:53.647

Modified: 2026-08-23T14:16:53.647

Link: CVE-2026-5389

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses