markdownify allows large headline prefixes such as <h9999999>, which causes memory consumptionGHSA-7mpr-5m44-h73r
LOWFix: matthewwithanm/python-markdownify@9595618GHSA-7mpr-5m44-h73r is a low-severity (CVSS 2.9) CWE-1284 vulnerability in markdownify. A fix is available for markdownify — see the affected versions and patch details below.
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-7mpr-5m44-h73r.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
markdownifyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
python-markdownify (aka markdownify) before 0.14.1 allows large headline prefixes such as <h9999999> in addition to <h1> through <h6>. This causes memory consumption.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | markdownify | all versions | 0.14.1pip install --upgrade 'markdownify==0.14.1' |
Affected Products
markdownifymatthewwithanmDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for markdownify, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update markdownify to 0.14.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-7mpr-5m44-h73r is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is GHSA-7mpr-5m44-h73r in your dependencies?
Find it across PyPI, including transitive dependencies.