How should we interpret CVSS severity scores?

CVSS estimates technical severity, but it does not automatically equal business risk. Prioritize using context like internet exposure, asset criticality, known exploitation, and whether compensating controls exist. A Medium CVSS on an exposed production system can be more urgent than a Critical on an isolated non-production host.

Vulnerability Database

Q: What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

Q: Why do vulnerabilities keep reappearing in our environment?

Recurring findings usually come from incomplete asset discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host.

Q: How do we prioritize remediation without burning out the team?

Use a repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress so remediation is steady, not reactive.

Q: How can SynScan help reduce vulnerability risk over time?

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.

363,159

Total vulnerabilities in the database

OpenList: Arbitrary File Read via Path Prefix Confusion in Share Creation API — github.com/OpenListTeam/OpenList/v4

Authorization Bypass Through User-Controlled Key

Summary

An authorization bypass vulnerability exists in the file sharing mechanism of Openlist. Due to a flawed, non-separator-aware path validation check, an authenticated user can create share links for files outside their restricted base directory. This allows an attacker to bypass tenant/user isolation and gain unauthorized read access to arbitrary files within the system.

Details

When a user attempts to create or update a file share, the application must verify that the requested file path falls within the user's assigned BasePath. However, in server/handles/sharing.go, this authorization check relies on a simple string prefix function: strings.HasPrefix(requested_path, user.BasePath).

Because strings.HasPrefix does not account for directory separators (e.g., /), an attacker whose BasePath is assigned to /base can supply a target path like /base2/secret_document.txt. The validation strings.HasPrefix("/base2/secret_document.txt", "/base") evaluates to true, successfully passing the authorization filter.

Once the share is created, the public share download/list handlers unwrap and serve the file based on the stored absolute path without re-verifying the creator's current directory scope, granting the attacker horizontal access to unauthorized data.

PoC

Prerequisites:

A system with at least two distinct directories at the root level: /base and /base2.
A sensitive file exists at /base2/secret.txt.
An attacker account with the CanShare permission enabled and its Base path strictly limited to /base.

Exploitation Steps:

Log in as the attacker account and obtain the JWT authorization token.
Send a POST request to create a new share, intentionally targeting the unauthorized sibling directory /base2:

POST /api/share/create HTTP/1.1
Host: &lt;your-openlist-host&gt;
Authorization: &lt;attacker-jwt-token&gt;
Content-Type: application/json

{
  &quot;files&quot;: [&quot;/base2/secret.txt&quot;],
  &quot;pwd&quot;: &quot;&quot;,
  &quot;max_accessed&quot;: 0
}

Observe the bypass: The API accepts the request and responds with a successful share creation message, returning a share_id.

The attacker can now access the public share endpoint (e.g., via the web UI or API /api/fs/list / /sd/<share-id>/...) to download or view /base2/secret.txt, completely bypassing their directory restrictions.

Impact

This is a High-severity Horizontal and Vertical Privilege Escalation vulnerability. A malicious user with basic sharing privileges can weaponize this path confusion to expose, read, and download any file from other users' directories or internal application paths, provided the target path shares the same string prefix as their own directory. This completely breaks the data isolation guarantees of the application.

Remediation Recommendations

Canonical Path Containment: Replace the raw strings.HasPrefix check with a robust, separator-aware path containment validation. Ensure both paths are normalized, and use logic such as: target == base || strings.HasPrefix(target, base + "/").

Centralized Validation Utility: Implement a dedicated function (e.g., utils.IsSubPath(base, target)) and apply it consistently across share creation, updating, and viewing handlers to prevent regressions.

Credits

Thai Son Dinh from VinSOC Labs (R&D)

Published: Jul 24, 2026
Updated: Jul 25, 2026
GHSA: GHSA-86cx-wwf4-phq4
Severity: Medium
Exploit:
CISA KEV:

CVSS v3:

Severity: Medium
Score: 6.5
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CWEs:

CWE-639

OWASP TOP 10:

A5 - Broken Access Control

Affected Software
References

Software	From	Fixed in
github.com/OpenListTeam/OpenList/v4	-	4.2.4

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.