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...

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...

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...

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...

SUSE SLES16 Security Update : python-mistune (SUSE-SU-2026:22655-1)

The remote SUSE Linux SLES16 / SLESSAP16 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:22655-1 advisory. This update for python-mistune fixes the following issues - CVE-2026-59922: quadratic-time parsing on long runs of some markers in...

openSUSE 16 Security Update : python-mistune (openSUSE-SU-2026:21339-1)

The remote openSUSE 16 host has a package installed that is affected by multiple vulnerabilities as referenced in the openSUSE-SU-2026:21339-1 advisory. This update for python-mistune fixes the following issues - CVE-2026-59922: quadratic-time parsing on long runs of some markers in formatting.py...

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...

Security update for python-mistune (moderate)

openSUSE security update: security update for python-mistune ------------------------------------------------------------- Announcement ID: openSUSE-SU-2026:21339-1 Rating: moderate References: bsc1271082 bsc1271117 bsc1271119 bsc1271121 bsc1271125 bsc1271127 bsc1271128 bsc1271131 bsc1271132...

SUSE-SU-2026:2949-1 Security update for python-mistune

This update for python-mistune fixes the following issue - CVE-2026-44898: improper sanitization of user-supplied HTML input in rendertocul can lead to XSS bsc1265052...

PYSEC-2026-2652 Mistune: Potential DoS via quadratic-time parsing in parse_link_text

Summary Mistune is vulnerable to a CPU exhaustion DoS due to superlinear approximately On² behavior in parselinktext. A relatively small input consisting of repeated characters causes significant parsing slowdown. Affected component mistune/inlineparser.py → parselinktext Description When parsing...

PYSEC-2026-2651 Mistune has a ReDoS in LINK_TITLE_RE that allows denial of service via crafted Markdown input

Summary A ReDoS Regular Expression Denial of Service vulnerability in LINKTITLERE allows an attacker who can supply Markdown for parsing to cause denial of service. A crafted 58-byte Markdown document blocks the parser for approximately 6 seconds measured on Apple M2, Python 3.14.3, with...