CVE-2021-23562 is a high-severity (CVSS 8.8) Unrestricted File Upload vulnerability in plupload. A fix is available for plupload — see the affected versions and patch details below.
Code injection in plupload
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-23562 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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.
pluploadnpmDescription
This affects the package plupload before 2.3.9. A file name containing JavaScript code could be uploaded and run. An attacker would need to trick a user to upload this kind of file.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | plupload | all versions | 2.3.9npm install plupload@2.3.9 |
Affected Products
pluploadtinyDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for plupload, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update plupload to 2.3.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-23562 is resolved across your whole dependency graph.
Workarounds
Treat uploaded files as untrusted until proven otherwise: validate the actual content type rather than the supplied extension, store uploads outside the web root on a volume mounted without execute permission, and rename them to server-generated identifiers so an attacker cannot choose the path a request will later resolve.
Frequently Asked Questions
Is CVE-2021-23562 in your dependencies?
Find it across npm, including transitive dependencies.