Uncontrolled Recursion Affecting mistune package, versions [,3.3.3)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published25 Aug 2026
- disclosed24 Aug 2026
- creditwan1yan
Introduced: 24 Aug 2026
NewCVE-2026-76098 (opens in a new tab)How to fix?
Upgrade mistune to version 3.3.3 or higher.
Overview
Affected versions of this package are vulnerable to Uncontrolled Recursion through the InlineParser emphasis processing in src/mistune/inline_parser.py. An attacker can crash the Python process by supplying Markdown with a very long run of emphasis markers, such as hundreds or thousands of consecutive * characters. The inline parser turns those markers into deeply nested emphasis and strong tokens, and rendering that token tree exhausts Python’s recursion limit. In applications that accept untrusted Markdown, this breaks page rendering or request handling for all users sharing the affected process.