CVE-2018-1000162 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in erusev/parsedown. A fix is available for erusev/parsedown — see the affected versions and patch details below.
Cross-site Scripting in Parsedown
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2018-1000162 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
erusev/parsedownReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Parsedown version prior to 1.7.0 contains a Cross Site Scripting (XSS) vulnerability in setMarkupEscaped for escaping HTML that can result in JavaScript code execution. This attack appears to be exploitable via specially crafted markdown that allows it to side step HTML escaping by breaking AST boundaries. This vulnerability appears to have been fixed in 1.7.0 and later.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | erusev/parsedown | all versions | 1.7.0composer require erusev/parsedown:^1.7.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for erusev/parsedown, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update erusev/parsedown to 1.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-1000162 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2018-1000162 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2018-1000162. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2018-1000162 in your dependencies?
O3 Security finds CVE-2018-1000162 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.