CVE-2026-59922

A flaw was found in Mistune, a Python Markdown parser. A remote attacker could exploit this vulnerability by providing specially crafted input containing specific marker pairs tilde, equals-sign, or caret. This crafted input causes the parser to perform quadratic work, leading to excessive CPU...

CVE-2026-59924

A flaw was found in Mistune, a Python Markdown parser. The Include.parse function does not properly verify user-supplied include paths, allowing an attacker to craft paths that can access files outside the intended markdown directory. This can lead to information disclosure when markdown files ar...

EUVD-2026-42336

Mistune renderers/html.safeurl: HARMFULPROTOCOLS list misses legacy and chained schemes that historically chain to javascript: execution...

GHSA-QFRW-5RXM-MHH2 Mistune renderers/html.safe_url: HARMFUL_PROTOCOLS list misses legacy and chained schemes that historically chain to `javascript:` execution

Summary Type: URL-scheme allowlist gap. The safeurl filter only blocks the four schemes javascript:, vbscript:, file:, data:. Several other schemes are accepted into rendered and tags despite being known XSS vectors in legacy or chain-handling browsers. The same gap applies to direct links,...

EUVD-2026-42330

Mistune toc / TableOfContents directive: heading IDs use predictable tocN numbering with no slugification, allowing collision with attacker-controlled id="tocN" content...

GHSA-R4RV-85JG-W4MF Mistune: Arbitrary File Read via Include directive path traversal

Summary A path traversal issue exists in mistune's Include directive when markdown files are processed using md.read. A crafted include path can cause files outside the intended markdown directory to be accessed. Details The issue occurs in the Include.parse method where user-supplied paths are...

EUVD-2026-42329

Mistune plugins/formatting: quadratic-time parsing on long runs of x, ==x==, and ^^x^^ markers strikethrough / mark / insert...

GHSA-C8J7-8CV4-2XMQ Mistune plugins/formatting: quadratic-time parsing on long runs of `~~x~~`, `==x==`, and `^^x^^` markers (strikethrough / mark / insert)

Summary Type: Algorithmic-complexity denial of service. A run of N closed pairs xx... or the analogous ==x== for mark, ^^x^^ for insert causes ON² work in the formatting parser. With the strikethrough, mark, or insert plugin enabled, an 8 KB input pegs the CPU for 4 seconds; 16 KB → 17 seconds...

GHSA-G97X-GVCM-X72H Mistune: XSS via unescaped class option in Admonition directive

In src/mistune/directives/admonition.py, the renderadmonition function concatenates the :class: option directly into the HTML class attribute without escaping lines 63-68. This allows attribute injection and XSS even when HTMLRendererescape=True is used. The directive name parameter is safe...

EUVD-2026-42331

Mistune: XSS via percent-encoded javascript URI bypass in safeurl...

GHSA-8C25-4J27-2RV3 Mistune: XSS via percent-encoded javascript URI bypass in safe_url()

Summary An XSS vulnerability in Mistune allows bypassing of safeurl protections via percent-encoded javascript URIs. Details The vulnerability exists in HTMLRenderer.safeurl in Mistune. The function is intended to block harmful URL schemes such as "javascript:" by checking the prefix of the...

GHSA-4J32-57V6-6G45 Mistune inline_parser: quadratic-time parsing on long runs of `**x**` and `***x***` emphasis pairs

Summary Type: Algorithmic-complexity DoS in core emphasis parsing. A long sequence of well-formed x strong or x strong-emphasis combined pairs causes ON² parser work. Distinct from the bracket-bomb DoS repetition and from the formatting-plugin DoS /==/^^; this one fires on default-config mistune...

EUVD-2026-42335

Mistune inlineparser: quadratic-time parsing on long runs of x and x emphasis pairs...

GHSA-8MPJ-M6QM-5QR8 Mistune directives/include: mutual `.. include::` recursion crashes the renderer with `RecursionError`, denial of service via two attacker-controlled markdown files

Summary Type: Uncontrolled recursion via mutual include. The Include directive checks for direct self-reference a.md cannot include a.md, but does not detect indirect cycles. Two markdown files that include each other a.md → includes b.md → includes a.md cause unbounded recursion until Python's...

EUVD-2026-42339

Mistune directives/include: mutual .. include:: recursion crashes the renderer with RecursionError, denial of service via two attacker-controlled markdown files...

GHSA-FFQ3-XPV3-J92Q Mistune block_parser: quadratic-time parsing on long lists of repeated reference-link definitions

Summary Type: Algorithmic-complexity DoS in reference-link definition handling. A markdown document with N reference-link definitions of the same key or many distinct keys takes ON² parser time. 5000 repeated a: u\n definitions take 1.1 second; 10000 → 4.5 seconds. File: src/mistune/blockparser.p...

EUVD-2026-42338

Mistune blockparser: quadratic-time parsing on long lists of repeated reference-link definitions...

Security Bulletin: Multiple vulnerabilities in IBM watsonx Orchestrate Developer Edition

Summary Multiple vulnerabilities were addressed in IBM watsonx Orchestrate Developer Edition version 2.13.0 Vulnerability Details CVEID:CVE-2023-5752 DESCRIPTION: When installing a package from a Mercurial VCS URL ie "pip install hg+..." with pip prior to v23.3, the specified Mercurial revision...

MGASA-2026-0254 Updated python-mistune package fixes security vulnerabilities

The updated python-mistune package fixes two security vulnerablities: Prior to 3.2.1, rendertocul builds a table-of-contents tree from a list of level, id, text tuples. Both the id value used as href="" and the text value used as the visible link label are inserted into tags via a plain Python...

Updated python-mistune package fixes security vulnerabilities

The updated python-mistune package fixes two security vulnerablities: Prior to 3.2.1, rendertocul builds a table-of-contents tree from a list of level, id, text tuples. Both the id value used as href="" and the text value used as the visible link label are inserted into tags via a plain Python...