How severe is CVE-2021-27907?

CVE-2021-27907 has a CVSS score of 5.4/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-27907?

CVE-2021-27907 affects the following packages: apache-superset (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2021-27907?

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.

How do I detect CVE-2021-27907 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for apache-superset. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2021-27907 if there is no patch (or I can't update yet)?

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 does O3 Security protect against CVE-2021-27907?

O3 pinpoints whether CVE-2021-27907 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2021-27907 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-27907 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-27907?

CVE-2021-27907 has an EPSS (Exploit Prediction Scoring System) score of 86.4%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

When was CVE-2021-27907 published, and has it been updated?

CVE-2021-27907 was published on March 5, 2021 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2021-27907: Apache Superset Stored XSS on Dashboard markdow…

EPSS Exploitation Probability

via FIRST.org ↗

86.4%probability of exploitation in next 30 days

Very High Risk100th percentile+83.88%

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.

Blast Radius

1 pkg affected

🐍apache-superset

Real-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

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`apache-superset`	all versions	0.38.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for apache-superset. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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 pinpoints whether CVE-2021-27907 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

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

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.

O3 Security · Impact-Aware SCA

Is CVE-2021-27907 in your dependencies?

O3 detects CVE-2021-27907 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

CVE-2021-27907