CVE-2026-59923
Last modified
CVE-2026-59923 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, HTMLRenderer.safe_url() does not block percent-encoded javascript URIs, allowing attacker-supplied Markdown links or images to bypass URL protections and execute script in rendered HTML. EPSS estimates a 0.20% chance of exploitation in the next 30 days.
Description
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, HTMLRenderer.safe_url() does not block percent-encoded javascript URIs, allowing attacker-supplied Markdown links or images to bypass URL protections and execute script in rendered HTML. This issue is fixed in version 3.3.0.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mistune Project | Mistune | < 3.3.0 |
References
- https://github.com/lepture/mistune/security/advisories/GHSA-8c25-4j27-2rv3Exploit, Vendor Advisory
- https://github.com/lepture/mistune/security/advisories/GHSA-8c25-4j27-2rv3Exploit, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2026-59923?
How severe is CVE-2026-59923?
How do I fix CVE-2026-59923?
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-59917Dell Display and Peripheral Manager (DDPM Windows), versions…7.8
- CVE-2026-59919Netty is an asynchronous, event-driven network application f…5.5
- CVE-2026-5992A vulnerability was determined in Tenda F451 1.0.0.7. This a…8.8
- CVE-2026-59920Netty is an asynchronous, event-driven network application f…6.5
- CVE-2026-59921Netty is an asynchronous, event-driven network application f…6.5
- CVE-2026-59922Mistune is a Python Markdown parser with renderers and plugi…7.5
- CVE-2026-59924Mistune is a Python Markdown parser with renderers and plugi…5.9
- CVE-2026-59925Mistune is a Python Markdown parser with renderers and plugi…7.5
- CVE-2026-59926Mistune is a Python Markdown parser with renderers and plugi…6.1
- CVE-2026-59927Mistune is a Python Markdown parser with renderers and plugi…5.3
- CVE-2026-59928Mistune is a Python Markdown parser with renderers and plugi…7.5
- CVE-2026-59929Mistune is a Python Markdown parser with renderers and plugi…6.1
Are you affected by CVE-2026-59923?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST