CVE-2026-59928
Fixed in a distro release EPSS <1%CVSS 7.5
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a Markdown document containing many repeated or distinct reference-link definitions causes quadratic work in src/mistune/block_parser.py and the ref_links environment dictionary handling, allowing denial of service through CPU exhaustion. This issue is fixed in version 3.3.0.
Products: lepture mistune
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| PyPI | mistune | 3.3.0 |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Debian 13 | mistune | no fix |
| Debian 14 | mistune | no fix |
| SUSE Linux Enterprise Server 16.0 | python-mistune | 3.1.3-160000.5.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | python-mistune | 3.1.3-160000.5.1 |
| Ubuntu 16.04 LTS | mistune | no fix |
| Ubuntu 18.04 LTS | mistune | no fix |
| Ubuntu 20.04 LTS | mistune | no fix |
| Ubuntu 22.04 LTS | mistune | no fix |
| Ubuntu 24.04 LTS | mistune | no fix |
| Ubuntu 25.10 | mistune | no fix |
| Ubuntu 26.04 LTS | mistune | no fix |
| Ubuntu 26.10 | mistune | no fix |
| openSUSE Leap 16.0 | python-mistune | 3.1.3-160000.5.1 |