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Filebrowser CVE-2021-37794

MEDIUM
Cross-site Scripting (XSS) (CWE-79)
2021-08-31 cve@mitre.org
5.4
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 5.4 (MEDIUM). Attack characteristics: network attack vector, low complexity, low privileges required, user interaction required.

Exploit ScenarioDerived

A remote attacker could inject malicious scripts into web pages viewed by other users by sending crafted requests to the affected application.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.8% exploitation probability (EPSS)

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AnalysisAI

A stored cross-site scripting (XSS) vulnerability exists in FileBrowser < v2.16.0 that allows an authenticated user authorized to upload a malicious .svg file which acts as a stored XSS payload. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. A stored cross-site scripting (XSS) vulnerability exists in FileBrowser < v2.16.0 that allows an authenticated user authorized to upload a malicious .svg file which acts as a stored XSS payload. If this stored XSS payload is triggered by an administrator it will trigger malicious OS commands on the server running the FileBrowser instance. Affected products include: Filebrowser Project Filebrowser.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.4 MEDIUM
AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

DescriptionNVD

A stored cross-site scripting (XSS) vulnerability exists in FileBrowser < v2.16.0 that allows an authenticated user authorized to upload a malicious .svg file which acts as a stored XSS payload. If this stored XSS payload is triggered by an administrator it will trigger malicious OS commands on the server running the FileBrowser instance.

Threat Intelligence Overview

EPSS Score
0.8%
Top 48% exploitable
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.8%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

28
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +27
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.

Affected Products (CPE)NVD

cpe:2.3:a:filebrowser_project:filebrowser:*:*:*:*:*:*:*:*
CVE-2026-29188 CRITICAL POC
9.1 Mar 05

Unauthorized file operations in File Browser before fix. PoC and patch available.

CVE-2023-39612 CRITICAL POC
9.0 Sep 16

A cross-site scripting (XSS) vulnerability in FileBrowser before v2.23.0 allows an authenticated attacker to escalate pr

CVE-2026-116682 HIGH POC
8.6 Oct 27

Symlink-following read paths in FileBrowser Quantum serve files from outside a user's assigned scope: download, preview,

CVE-2026-73612 HIGH POC
8.6 Aug 13

Recursive operation authorization bypass in File Browser before v2.63.22 permits any authenticated user to copy, rename,

CVE-2026-25890 HIGH POC
8.1 Feb 09

Path normalization bypass in Filebrowser prior to 2.57.1 allows authenticated users to circumvent file access restrictio

CVE-2025-52903 HIGH POC
8.0 Jun 26

File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, previ

CVE-2025-52904 HIGH POC
8.0 Jun 26

File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, previ

CVE-2025-52995 HIGH POC
8.0 Jun 30

File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, previ

CVE-2026-54910 HIGH POC
7.7 Jul 20

Arbitrary file read in FileBrowser Quantum (gtsteffaniak/filebrowser) before 1.4.3-beta lets any authenticated user, reg

CVE-2026-73611 HIGH POC
7.6 Aug 13

File Browser versions 2.50.0 through 2.63.21 permit indefinite session persistence via expired JWT tokens when proxy aut

CVE-2025-52902 HIGH POC
7.6 Jun 26

File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, previ

CVE-2026-73613 HIGH POC
7.2 Aug 13

Arbitrary file deletion in filebrowser before 2.63.19 allows authenticated users holding only Create permission to delet

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