# CVE-2023-26303: python3-markdown-it: Denial of service could be caused to markdown-it-py, before v2.2.0, if anattacker was allowed to force null assertion...

CVE-2023-26303 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2023-26303, released February 23, 2023. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2023-26303
- Priority: Routine
- CVSS: 5.5 (Medium)
- EPSS: 0.0023
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 23, 2023

## Description

Denial of service could be caused to markdown-it-py, before v2.2.0, if anattacker was allowed to force null assertions with specially crafted input.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | markdown-it-py Debian 12.15 (bookworm) | 2.1.0-5 | [DEBIAN-CVE-2023-26303](https://patchblox.com/security/data/fix/linux/debian-cve-2023-26303.md) | Feb 23, 2023 |
| Linux | markdown-it-py Debian 13.5 (trixie) | 2.1.0-5 | [DEBIAN-CVE-2023-26303](https://patchblox.com/security/data/fix/linux/debian-cve-2023-26303.md) | Feb 23, 2023 |
| Linux | markdown-it-py Debian 14 | 2.1.0-5 | [DEBIAN-CVE-2023-26303](https://patchblox.com/security/data/fix/linux/debian-cve-2023-26303.md) | Feb 23, 2023 |
| Linux | python3-markdown-it Ubuntu 24.10 (oracular) | 2.1.0-4ubuntu1 | [python3-markdown-it 2.1.0-4ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-python3-markdown-it-2.1.0-4ubuntu1.md) | Jan 16, 2026 |
| Linux | python3-markdown-it Ubuntu 25.04 (plucky) | 2.1.0-4ubuntu1 | [python3-markdown-it 2.1.0-4ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-python3-markdown-it-2.1.0-4ubuntu1.md) | Jan 16, 2026 |

---

Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.