What is CVE-2026-44708?

CVE-2026-44708 is a medium-severity vulnerability in Lepture Mistune, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-05-26.

How severe is CVE-2026-44708?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Lepture Mistune

CVE-2026-44708

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, the mistune math plugin renders inline math ($...$) and block math ($$...$$) by concatenating the raw user-supplied content directly into the HTML output without any HTML escaping. This occurs even when the parser is explicitly created with escape=True, which is supposed to guarantee that all user-controlled text is sanitised before reaching the DOM. This vulnerability is fixed in 3.2.1.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-05-26 · last modified 2026-07-24.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (18.2th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 18.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000

Affected products

Lepture Mistune — versions < 3.2.1
Mistune Project

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/lepture/mistune/releases/tag/v3.2.1 (Product, Release Notes)
github.com/lepture/mistune/security/advisories/GHSA-8g87-j6q8-g93x (Exploit, Vendor Advisory)

Frequently asked questions

What is CVE-2026-44708?: CVE-2026-44708 is a medium-severity vulnerability in Lepture Mistune, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-05-26.
How severe is CVE-2026-44708?: Medium severity. CVSS v3 base score is 6.1 out of 10.