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CVE-2021-23439

CVE-2021-23439:
Cross-site Scripting in file-upload-with-preview

4.2

CVSS Score
3.1

Basic Information

CVE ID
CVE-2021-23439
GHSA ID
GHSA-97pv-4338-r5vp
EPSS Score
0.60629%
CWE
CWE-79
Published
9/7/2021
Updated
2/1/2023
KEV Status
No
Technology
TechnologyJavaScript

Technical Details

CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
Package NameEcosystemVulnerable VersionsFirst Patched Version
file-upload-with-previewnpm< 4.2.04.2.0

Vulnerability Intelligence
Miggo AIMiggo AI

Miggo AIRoot Cause Analysis

The vulnerability stems from improper neutralization of file names before DOM insertion. The advisory references line 168 in the source file, which in the patched version (PR #40) shows security-focused changes. The fix involved using textContent instead of innerHTML for filename display, indicating the original implementation directly injected user-controlled filenames into DOM elements without sanitization. This pattern matches classic stored XSS vulnerability patterns where user-controlled input is rendered unsafely.

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

WAF Protection Rules

WAF Rule

T*is *****ts t** p**k*** *il*-uplo**-wit*-pr*vi*w ***or* *.*.*. * *il* *ont*inin* m*li*ious J*v*S*ript *o** in t** n*m* **n ** uplo**** (* us*r n***s to ** tri*k** into uplo**in* su** * *il*).

Reasoning

T** vuln*r**ility st*ms *rom improp*r n*utr*liz*tion o* *il* n*m*s ***or* *OM ins*rtion. T** **visory r***r*n**s lin* *** in t** sour** *il*, w*i** in t** p*t**** v*rsion (PR #**) s*ows s**urity-*o*us** ***n**s. T** *ix involv** usin* `t*xt*ont*nt` i