CVE-2026-71488 league/commonmark: Quadratic-time denial of service when parsing crafted Markdown

league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 0.6.0 until 2.9.0, specially crafted Markdown lines can cause the parser to have quadratic time complexity when converting, because several parsing paths repeatedly rescan growing portions of a line to translat...

CVE-2026-71488

The CVE concerns league/commonmark (PHP) with a vulnerability in versions 0.6.0–2.9.0 where crafted Markdown can trigger quadratic-time processing during parsing/conversion. The root cause involves repeatedly rescanning growing segments to translate character positions to byte positions, and the ...

GHSA-V245-V573-V5VM linkify-it: Quadratic-complexity DoS via the `mailto:` validator scan-loop on attacker text

Summary linkify-it's schema-scan loop .test / .match, the documented public API invokes the mailto: schema validator at every mailto: occurrence in the input text. For each occurrence the validator does text.slicepos an On copy and runs an email regex whose local-part class srcemailname greedily...

Tornado: Quadratic DoS via Crafted Multipart Parameters

Summary The parseparam function in Tornado's httputil.py is used to parse specific HTTP header values, such as those in multipart/form-data. This function uses an inefficient algorithm that repeatedly calls string.count within a nested loop while processing quoted semicolons e.g., param=";". As a...

CVE-2026-59870

CVE-2026-59870 affects js-yaml prior to 5.2.1. The YAML11_SCHEMA’s handling of the !!omap tag in omap.ts performs a linear duplicate-key scan on each insertion, causing O(n^2) CPU usage when yaml.load() parses crafted ordered-map documents. Red Hat and NVD entries confirm this results in CPU-inte...

CVE-2026-59870 js-yaml quadratic-complexity denial of service via YAML11_SCHEMA !!omap parsing

js-yaml is a JavaScript YAML parser and dumper. From 5.0.0 before 5.2.1, YAML11SCHEMA support for the !!omap tag in src/tag/sequence/omap.ts uses omapTag.addItem to perform a linear duplicate-key scan on every insertion, causing On^2 CPU consumption when yaml.load parses a crafted ordered-map...

CVE-2025-67726 Tornado is Vulnerable to Quadratic DoS via Crafted Multipart Parameters

Tornado is a Python web framework and asynchronous networking library. Versions 6.5.2 and below use an inefficient algorithm when parsing parameters for HTTP header values, potentially causing a DoS. The parseparam function in httputil.py is used to parse specific HTTP header values, such as thos...

CVE-2025-67726 Tornado is Vulnerable to Quadratic DoS via Crafted Multipart Parameters

Tornado is a Python web framework and asynchronous networking library. Versions 6.5.2 and below use an inefficient algorithm when parsing parameters for HTTP header values, potentially causing a DoS. The parseparam function in httputil.py is used to parse specific HTTP header values, such as thos...