CVE-2021-47899 Vulnerability Analysis & Exploit Details

CVE-2021-47899
Vulnerability Scoring

4.0
/10
Moderate Risk

Exploiting CVE-2021-47899 requires specific conditions, leading to a moderate security impact.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Local
    Vulnerability requires local system access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2021-47899 Details

Status: Awaiting Analysis

Last updated: 🕒 26 Jan 2026, 15:03 UTC
Originally published on: 🕔 23 Jan 2026, 17:16 UTC

Time between publication and last update: 2 days

CVSS Release: version 3

CVSS3 Source

disclosure@vulncheck.com

CVSS3 Type

Secondary

CVSS3 Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVE-2021-47899 Vulnerability Summary

CVE-2021-47899: YetiShare File Hosting Script 5.1.0 contains a server-side request forgery vulnerability that allows attackers to read local system files through the remote file upload feature. Attackers can exploit the url parameter in the url_upload_handler endpoint to access sensitive files like /etc/passwd by using file:/// protocol.

Assessing the Risk of CVE-2021-47899

Access Complexity Graph

The exploitability of CVE-2021-47899 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2021-47899

With low attack complexity and no required privileges, CVE-2021-47899 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2021-47899, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2021-47899, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2021-47899 has no significant impact on data confidentiality.
  • Integrity: Low
    Exploiting CVE-2021-47899 may cause minor changes to data without severely impacting its accuracy.
  • Availability: None
    CVE-2021-47899 does not impact system availability.

CVE-2021-47899 References

External References

CWE Common Weakness Enumeration

CWE-434

CAPEC Common Attack Pattern Enumeration and Classification

  • Accessing Functionality Not Properly Constrained by ACLs CAPEC-1 In applications, particularly web applications, access to functionality is mitigated by an authorization framework. This framework maps Access Control Lists (ACLs) to elements of the application's functionality; particularly URL's for web apps. In the case that the administrator failed to specify an ACL for a particular element, an attacker may be able to access it with impunity. An attacker with the ability to access functionality not properly constrained by ACLs can obtain sensitive information and possibly compromise the entire application. Such an attacker can access resources that must be available only to users at a higher privilege level, can access management sections of the application, or can run queries for data that they otherwise not supposed to.

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