{"cve":"CVE-2026-44899","nvd":{"published":"2026-05-26T21:16:39.953","modified":"2026-07-24T11:10:00.170","status":"Analyzed","description":"Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, the Image directive plugin validates the :width: and :height: options with a regex compiled as _num_re = re.compile(r\"^\\d+(?:\\.\\d*)?\"). When the validated value is not a plain integer, render_block_image() inserts it directly into a style=\"width:...;\" or style=\"height:...;\" attribute. Because the value was accepted by the prefix-only regex, any CSS after the leading digits reaches the style= attribute verbatim and without escaping. This vulnerability is fixed in 3.2.1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-79"],"references":["https://github.com/lepture/mistune/releases/tag/v3.2.1","https://github.com/lepture/mistune/security/advisories/GHSA-ccfx-mfmx-2fx9","https://github.com/lepture/mistune/security/advisories/GHSA-ccfx-mfmx-2fx9"],"products":["mistune_project:mistune"],"source":"nvd","synced_at":"2026-10-19T22:36:28.938604137+00:00"},"epss":{"cve":"CVE-2026-44899","score":0.00228,"percentile":0.13623,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-ccfx-mfmx-2fx9","url":"https://osv.dev/vulnerability/GHSA-ccfx-mfmx-2fx9","summary":"Mistune Image Directive CSS Injection Vulnerability","modified":"2026-07-13T07:26:45.210699576Z","packages":[{"ecosystem":"PyPI","name":"mistune","purl":"pkg:pypi/mistune","ranges":[">=3.2.0 <3.2.1"],"fixed":["3.2.1"]}]},{"id":"PYSEC-2026-2209","url":"https://osv.dev/vulnerability/PYSEC-2026-2209","summary":"","modified":"2026-07-13T07:15:29.089597285Z","packages":[{"ecosystem":"PyPI","name":"mistune","purl":"pkg:pypi/mistune","ranges":["<3.2.1"],"fixed":["3.2.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}