GHSA-wvhm-4hhf-97x9 is a high-severity (CVSS 7.1) Cross-site Scripting (XSS) vulnerability in prismjs. A fix is available for prismjs — see the affected versions and patch details below.
Cross-Site Scripting in Prism
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
GHSA-wvhm-4hhf-97x9 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 378,156 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
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
prismjsnpmDescription
Impact
The easing preview of the Previewers plugin has an XSS vulnerability that allows attackers to execute arbitrary code in Safari and Internet Explorer.
This impacts all Safari and Internet Explorer users of Prism >=v1.1.0 that use the Previewers plugin (>=v1.10.0) or the Previewer: Easing plugin (v1.1.0 to v1.9.0).
Patches
This problem is patched in v1.21.0.
Workarounds
To workaround the issue without upgrading, disable the easing preview on all impacted code blocks. You need Prism v1.10.0 or newer to apply this workaround.
References
The vulnerability was introduced by this commit on Sep 29, 2015 and fixed by Masato Kinugawa (#2506).
For more information
If you have any questions or comments about this advisory, please open an issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | prismjs | ≥ 1.1.0&&< 1.21.0 | 1.21.0npm install prismjs@1.21.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for prismjs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update prismjs to 1.21.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wvhm-4hhf-97x9 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 GHSA-wvhm-4hhf-97x9 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-wvhm-4hhf-97x9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-wvhm-4hhf-97x9 in your dependencies?
O3 Security finds GHSA-wvhm-4hhf-97x9 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.