Mistune 3.0.0 before 3.3.0 Denial of Service via Nested Bracket Parsing
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 3.3.0
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
Mistune, a Python Markdown parsing library, is affected by this vulnerability. Attackers can send specially crafted Markdown containing deeply nested square brackets, causing the parser to consume excessive CPU time and potentially make the affected service unresponsive.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
Mistune from 3.0.0 before 3.3.0 contains an algorithmic complexity denial of service vulnerability in the parse_link_text function in src/mistune/helpers.py. Attackers can submit markdown with deeply nested square brackets triggering quadratic parsing time, exhausting server CPU with small crafted requests.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- lepture mistune
From 3.0.0 · fixed in 3.3.0