PatchTheCVECVE-2021-23439: This affects the package file-upload-with-preview before 4.2.0
CVE-2021-23439 is a medium-severity flaw (CVSS 4.2) affecting file-upload-with-preview. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
This affects the package file-upload-with-preview before 4.2.0. A file containing malicious JavaScript code in the name can be uploaded (a user needs to be tricked into uploading such a file).
Why this priority
- No elevated risk signals yet
A fixed release or distro patch exists.
Risk facts
| CVSS score | 4.2 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | High |
| Privileges needed | None |
| User interaction | Required |
| EPSS exploit chance | 0.9% (top 41%) |
| CISA exploited list | No |
| Weakness | CWE-79 |
| Published | 2021-09-05 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-23439?
file-upload-with-preview: upgrade to 4.2.0. Exact commands for each OS are on this page.
Is CVE-2021-23439 being exploited?
CVE-2021-23439 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-23439 affect?
CVE-2021-23439 affects file-upload-with-preview. Severity is medium (CVSS 4.2). This affects the package file-upload-with-preview before 4.2.0. A file containing malicious JavaScript code in the name can be uploaded (a user needs to be tricked into uploading such a file).
How urgent is CVE-2021-23439?
Priority 30/100. No elevated risk signals yet.