CVE-2021-27907 — apache-superset
MEDIUMCVE-2021-27907 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in apache-superset. EPSS puts its 30-day exploitation probability at 86.4% (100th percentile). A fix is available for apache-superset — see the affected versions and patch details below.
Apache Superset Stored XSS on Dashboard markdown
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-2021-27907 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 377,333 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
apache-supersetReal-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
Apache Superset up to and including 0.38.0 allowed the creation of a Markdown component on a Dashboard page for describing chart's related information. Abusing this functionality, a malicious user could inject javascript code executing unwanted action in the context of the user's browser. The javascript code will be automatically executed (Stored XSS) when a legitimate user surfs on the dashboard page. The vulnerability is exploitable creating a “div” section and embedding in it a “svg” element with javascript code.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | apache-superset | all versions | 0.38.1pip install --upgrade 'apache-superset==0.38.1' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for apache-superset, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update apache-superset to 0.38.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-27907 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-2021-27907 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2021-27907. 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-2021-27907 in your dependencies?
O3 Security finds CVE-2021-27907 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.