CVE catalog
CVE-2026-59923
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 ima
- Severity
- Medium · CVSS 6.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.35% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | mistune | sid | 3.4.0-1 | fixed |
| Debian | mistune | forky | 3.1.4-1 | vulnerable |
| Debian | mistune | trixie | 3.1.3-1 | vulnerable |
| Debian | mistune | bookworm | 2.0.4-1 | vulnerable |
| Cpe | mistune | Not reported | Not reported | vulnerable |
| Cpe | mistune | Not reported | 3.3.0 | fixed |
| Pip | mistune | Not reported | 3.3.0 | fixed |
| PyPI | mistune | Not reported | 3.3.0 | fixed |
| Cpe | mistune | Not reported | 3.3.0 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | mistune | source | sid | 3.3.4-1 | not yet assigned | Not reported | [1141770] |
| Debian | mistune | source | forky | (unfixed) | not yet assigned | Not reported | [1141770] |
| Debian | mistune | source | trixie | (unfixed) | not yet assigned | Not reported | [1141770] |
| Debian | mistune | source | bookworm | (unfixed) | not yet assigned | Not reported | [1141770] |
| Cpe | mistune | cpe | Not reported | 3.3.0 | Not reported | Not reported | Not reported |
| Pip | mistune | pip | Not reported | 3.3.0 | Not reported | Not reported | Not reported |
| PyPI | mistune | PyPI | Not reported | 3.3.0 | Not reported | Not reported | Not reported |
| Cpe | mistune | cpe | Not reported | 3.3.0 | Not reported | NVD-CVE-2026-59923 | Not reported |
Notes
[trixie] mistune: Minor issue [bookworm] mistune: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [python3-mistune]Affected
Source package: [mistune]
Details (2)
2.0.4-1· all · bookwormAffected
nvd · mistune · debian · bookworm; nvd · mistune · debian · 12
2.0.4-1· all · bookwormAffected
nvd · mistune · debian · bookworm; nvd · mistune · debian · 12
[Debian 13 (Trixie)]
- [python3-mistune]Affected
Source package: [mistune]
Details (2)
3.1.3-1· all · trixieAffected
nvd · mistune · debian · 13
3.1.3-1· all · trixieAffected
nvd · mistune · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/suse-su-2026_22655-1.json]
- [https://github.com/advisories/GHSA-8c25-4j27-2rv3]
- [https://github.com/lepture/mistune/commit/c7101fcbb6e8790e8e39157c5ca2238fc6dd6cbc]
- [https://github.com/lepture/mistune/releases/tag/v3.3.0]
- [https://github.com/lepture/mistune/security/advisories/GHSA-8c25-4j27-2rv3]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-59923]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-59923]
- [https://osv.dev/vulnerability/GHSA-8c25-4j27-2rv3]
- [https://osv.dev/vulnerability/PYSEC-2026-2211]
- [https://security-tracker.debian.org/tracker/CVE-2026-59923]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-59923.json]
[Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]