CVE-2025-13947: WebKitGTK Information Disclosure Flaw

CVE-2025-13947 Overview

A security vulnerability has been identified in WebKitGTK that allows remote, user-assisted information disclosure through an abuse of the file drag-and-drop mechanism. The flaw exists because WebKitGTK does not properly verify that drag operations originate from outside the browser, enabling attackers to potentially exfiltrate any file the user is permitted to read on the target system.

Critical Impact

Remote attackers can exploit this vulnerability to read sensitive files from the victim's system, potentially exposing credentials, configuration data, cryptographic keys, or other confidential information accessible by the user.

Affected Products

• WebKitGTK (all versions prior to security patches)
• Linux distributions using WebKitGTK (Red Hat Enterprise Linux, Fedora, etc.)
• Applications built on WebKitGTK rendering engine

Discovery Timeline

• 2025-12-03 - CVE-2025-13947 published to NVD
• 2026-04-20 - Last updated in NVD database

Technical Details for CVE-2025-13947

Vulnerability Analysis

This vulnerability is classified under CWE-346 (Origin Validation Error), indicating a fundamental failure in validating the source of drag-and-drop operations. The WebKitGTK rendering engine processes drag events without adequately distinguishing between legitimate user-initiated file drags from the operating system's file manager and potentially malicious drag events simulated or manipulated by web content.

When a user interacts with a malicious webpage, an attacker can craft content that tricks the browser into accepting what appears to be a file drag operation. Because WebKitGTK does not enforce proper origin checks on these operations, the browser may process the drag as if it originated from outside the browser context, allowing the attacker to specify arbitrary file paths and exfiltrate their contents.

The attack requires user interaction, as the victim must perform some action (such as dragging content or clicking on malicious elements) for the exploitation to succeed. However, social engineering techniques can readily coerce users into performing the necessary actions without understanding the security implications.

Root Cause

The root cause is an origin validation error (CWE-346) in WebKitGTK's drag-and-drop event handling mechanism. The browser engine fails to properly distinguish between drag operations that genuinely originate from outside the browser (e.g., from the user's file manager) versus those that are initiated or manipulated by web content within the browser. This missing validation allows malicious web pages to abuse the file access capabilities typically reserved for legitimate cross-application drag operations.

Attack Vector

The attack is network-based and requires user interaction. An attacker hosts a malicious webpage that contains specially crafted elements designed to manipulate the drag-and-drop mechanism. When a victim visits this page and interacts with it (through actions like dragging content), the malicious page can leverage the unvalidated drag operations to access local files.

The attacker can target specific files by path, including configuration files, SSH keys, browser cookies, or any other files readable by the user. The disclosed file contents can then be exfiltrated to attacker-controlled servers, resulting in significant data exposure.

For technical details on the vulnerability mechanism, refer to the WebKit Bug Report #271957 and the Red Hat CVE Analysis.

Detection Methods for CVE-2025-13947

Indicators of Compromise

• Unusual outbound network connections from browser processes to unknown external servers following user interaction with web content
• Unexpected file access patterns by WebKitGTK-based applications, particularly reads of sensitive configuration files or credential stores
• Browser processes accessing files outside normal browsing directories (e.g., ~/.ssh/, ~/.gnupg/, or application configuration directories)

Detection Strategies

• Monitor WebKitGTK-based application processes for anomalous file system access patterns, particularly reads of sensitive files
• Implement network monitoring to detect large data transfers from browser processes to untrusted external destinations
• Deploy endpoint detection and response (EDR) solutions capable of correlating browser activity with file system operations
• Review web server logs for requests to pages known to exploit this vulnerability

Monitoring Recommendations

• Enable enhanced logging for WebKitGTK-based applications to capture drag-and-drop events and associated file operations
• Configure security information and event management (SIEM) systems to alert on browser processes accessing sensitive file paths
• Monitor for indicators of data staging or exfiltration following browser activity

How to Mitigate CVE-2025-13947

Immediate Actions Required

• Update WebKitGTK packages to the latest patched versions available from your distribution vendor
• Apply all relevant Red Hat security advisories if running RHEL or derivative distributions
• Restrict user access to sensitive files where possible through file system permissions
• Educate users about the risks of interacting with untrusted web content

Patch Information

Red Hat has released multiple security advisories addressing this vulnerability across various product versions. Organizations running affected systems should apply the appropriate patches immediately:

• RHSA-2025:22789
• RHSA-2025:22790
• RHSA-2025:23110
• RHSA-2025:23433
• RHSA-2025:23434
• RHSA-2025:23451
• RHSA-2025:23452
• RHSA-2025:23583
• RHSA-2025:23591
• RHSA-2025:23742
• RHSA-2025:23743

For additional details, consult the Red Hat Bug Report #2418576.

Workarounds

• Limit use of WebKitGTK-based browsers and applications for browsing untrusted websites until patches are applied
• Use alternative browsers that are not affected by this vulnerability for sensitive operations
• Implement strict file permissions to limit the impact of potential file disclosure
• Consider deploying browser isolation solutions to contain potential exploitation attempts

# Update WebKitGTK on Red Hat-based systems
sudo dnf update webkit2gtk3 webkit2gtk4.0 webkit2gtk4.1

# Verify installed WebKitGTK version
rpm -q webkit2gtk3 webkit2gtk4.0 webkit2gtk4.1