pymdown-extensions: exponential-backtracking ReDoS in caret, tilde, betterem, and magiclink inline processors

SummaryFour inline processors in pymdown-extensions contain regular expressions withexponential backtracking. A single untrusted Markdown line under50 bytes drives markdown.markdown into unbounded CPU on the rendering threadseconds at 45 bytes, growing exponentially with each added character. All...

PYSEC-2026-3654 pymdown-extensions: exponential-backtracking ReDoS in caret, tilde, betterem, and magiclink inline processors

Summary Four inline processors in pymdown-extensions contain regular expressions with exponential backtracking. A single untrusted Markdown line under 50 bytes drives markdown.markdown into unbounded CPU on the rendering thread seconds at 45 bytes, growing exponentially with each added character...

pymdown-extensions: exponential-backtracking ReDoS in caret, tilde, betterem, and magiclink inline processors

Summary Four inline processors in pymdown-extensions contain regular expressions with exponential backtracking. A single untrusted Markdown line under 50 bytes drives markdown.markdown into unbounded CPU on the rendering thread seconds at 45 bytes, growing exponentially with each added character...

Regular Expression Denial of Service (ReDoS)

Overview pymdown-extensions is an Extension pack for Python Markdown. Affected versions of this package are vulnerable to Regular Expression Denial of Service ReDoS in the processing of Markdown input by certain inline processors, specifically when handling crafted delimiter runs in the caret,...

GHSA-GM37-52C6-37MW pymdown-extensions: exponential-backtracking ReDoS in caret, tilde, betterem, and magiclink inline processors

Summary Four inline processors in pymdown-extensions contain regular expressions with exponential backtracking. A single untrusted Markdown line under 50 bytes drives markdown.markdown into unbounded CPU on the rendering thread seconds at 45 bytes, growing exponentially with each added character...

CVE-2026-67422

CVE-2026-67422 affects pymdown-extensions up to version 11.0, where four inline processors—caret, tilde, betterem, and magiclink—use regex patterns whose groups can partition delimiter runs in exponentially many ways. This causes catastrophic backtracking and unbounded CPU usage when rendering a ...

CVE-2026-67422 pymdown-extensions: Exponential-backtracking ReDoS in caret, tilde, betterem, and magiclink inline processors

pymdown-extensions is a collection of extensions for the Python Markdown library. In versions up to and including 11.0, four inline processors caret, tilde, betterem, and magiclink use regular expressions whose content groups can partition a run of delimiter characters in exponentially many ways,...

CVE-2026-67422 pymdown-extensions: Exponential-backtracking ReDoS in caret, tilde, betterem, and magiclink inline processors

pymdown-extensions is a collection of extensions for the Python Markdown library. In versions up to and including 11.0, four inline processors caret, tilde, betterem, and magiclink use regular expressions whose content groups can partition a run of delimiter characters in exponentially many ways,...

PT-2026-68773

Name of the Vulnerable Software and Affected Versions pymdown-extensions versions prior to 11.0.1 Description Four inline processors caret, tilde, betterem, and magiclink use regular expressions that can cause catastrophic backtracking—a condition where the regex engine takes an exponential amoun...

CVE-2026-67422: Inefficient Regular Expression Complexity

pymdown-extensions is a collection of extensions for the Python Markdown library. In versions up to and including 11.0, four inline processors caret, tilde, betterem, and magiclink use regular expressions whose content groups can partition a run of delimiter characters in exponentially many ways,...