CVE-2019-25781
Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link…
- Risk score
- 60/100
- CVSS
- 7.5 v3.1
- Published
- 29 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadrat…
- Affected
- See advisory
- Fix
- Apply the vendor's security update; see the linked advisory.
- Exploitation
- No known exploitation
Why it is Amber
- CVSS 7.5 high
- Remotely exploitable without logging in
- On your watchlist: python
References
- https://github.com/Python-Markdown/markdown
- https://github.com/Python-Markdown/markdown/blob/b41e0aaf1181f1a8cb200cf5a815aad7c0020d23/markdown/inlinepatterns.py#L1155-L1172
- https://github.com/Python-Markdown/markdown/issues/1654
- https://github.com/Python-Markdown/markdown/issues/798
- https://www.vulncheck.com/advisories/python-markdown-3.0-through-3.11.2-denial-of-service-via-link-bracket-parsing
Original description
Python-Markdown 3.0 through 3.11.2 contains an algorithmic complexity vulnerability in inline link parsing that allows remote attackers to exhaust CPU through unmatched brackets. Attackers can submit short Markdown containing repeated [ or ![ characters, forcing LinkInlineProcessor.getText() and getLink() into quadratic scans that keep workers busy for minutes.
Last activity 29 Oct 2026. Patch Forecast updates every hour.