CVE-2025-13947: 
Rocky Linux vulnerability analysis and mitigation

CVE-2025-13947 is a remote, user-assisted information disclosure vulnerability in WebKitGTK, the GTK port of the WebKit rendering engine. The flaw allows a malicious website to read arbitrary local files accessible to the user by abusing the file drag-and-drop mechanism — WebKitGTK fails to verify that drag operations originate from outside the browser before granting access to the referenced file path. Affected software includes WebKitGTK versions prior to 2.50.3, impacting distributions such as Red Hat Enterprise Linux 7, 8, and 9, Debian, Ubuntu, Fedora, SUSE, and others. The vulnerability was disclosed on December 3, 2025, and fixed upstream in WebKitGTK 2.50.3. It carries a CVSS v3.1 base score of 7.4 (High) (Red Hat CVE, Red Hat Bugzilla).

The root cause is an Origin Validation Error (CWE-346): WebKitGTK does not verify that a drag-and-drop operation originates from outside the browser window before processing the associated file URI. A crafted webpage can present an innocent-looking drag target (e.g., a UI element prompting the user to drag something), and when the user performs the drag action, the page gains access to the file path and contents of the dragged item — even if the drag was initiated from within the browser's own context. The attack vector is network-based and requires user interaction (the victim must perform a drag action on a malicious page), but no privileges or authentication are required. No public proof-of-concept exploit code has been identified, but the mechanism is straightforward to abuse given the detailed public description (Red Hat Bugzilla, Red Hat CVE).

Successful exploitation results in high confidentiality impact: an attacker-controlled website can exfiltrate the contents of any file the victim user has read access to, including sensitive files such as SSH private keys, configuration files, browser cookies, or credential stores. The scope is changed (cross-boundary), meaning the malicious web page can access local filesystem resources outside the browser's normal security boundary. There is no integrity or availability impact, and exploitation does not directly enable lateral movement, but exfiltrated credentials or keys could facilitate further compromise (Red Hat CVE, Red Hat Bugzilla).

No public exploit code or active in-the-wild exploitation has been reported for CVE-2025-13947. The EPSS score is approximately 0.039% (very low probability of exploitation in the near term). The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires user interaction — the victim must perform a drag action while visiting a malicious page — which limits opportunistic mass exploitation, though targeted social engineering attacks are plausible (Red Hat CVE).

1. Set up a malicious webpage: The attacker hosts a webpage with a visually deceptive drag-and-drop interface (e.g., a fake file upload zone or game element) designed to prompt the user to drag something on the page.
2. Lure the victim: The attacker directs the victim to the malicious page via phishing, malvertising, or a compromised site. The victim must be using a GTK-based application that embeds WebKitGTK (e.g., GNOME Web, Evolution, or another GTK app using WebKit).
3. Trigger the drag action: The attacker's page uses JavaScript event listeners (dragover, drop) to capture drag events. Because WebKitGTK does not validate that the drag originated from outside the browser, an internal drag (e.g., dragging a page element) can expose file URIs.
4. Capture file contents: When the user performs the drag, the page's JavaScript receives the file path or file data via the DataTransfer API, which the page then exfiltrates to an attacker-controlled server via an HTTP request.
5. Exfiltrate sensitive data: The attacker retrieves the contents of the exposed file (e.g., ~/.ssh/id_rsa, ~/.bash_history, or application config files) from their server (Red Hat Bugzilla).

• Network: Unexpected outbound HTTP/HTTPS POST requests from a WebKitGTK-based application to unknown external hosts shortly after a user performs a drag-and-drop action in a browser or embedded web view; requests containing Base64-encoded or URL-encoded file content in the body.
• Logs: Web server access logs on attacker infrastructure showing file content submissions; application logs from GTK-based browsers showing access to local file:// URIs from web content contexts.
• Process: WebKitGTK web process (WebKitWebProcess) making network connections to external hosts immediately following user drag interactions within a web page.

The upstream fix was released in WebKitGTK 2.50.3. Red Hat issued multiple security advisories addressing this CVE across RHEL 7, 8, and 9 variants, all delivering webkit2gtk3-2.50.3-1.elX packages (e.g., RHSA-2025:22789 for RHEL 8, RHSA-2025:22790 for RHEL 9, RHSA-2025:23110 for RHEL 9.6 EUS). Debian, Ubuntu, Fedora, SUSE, Mageia, AlmaLinux, Rocky Linux, and other distributions have also released updated packages. The primary remediation is to update WebKitGTK to version 2.50.3 or later via the distribution's package manager. No configuration-based workaround is available; upgrading is the only effective mitigation (Red Hat RHSA-2025:22789, Red Hat RHSA-2025:22790, Red Hat RHSA-2025:23110).

GNOME developer Michael Catanzaro published a blog post on December 9, 2025, describing the vulnerability as a "significant drag-and-drop vulnerability in WebKitGTK," providing technical context and urging users to update (GNOME Blog). The vulnerability was also discussed on the oss-security mailing list in December 2025. The CISA Vulnerability Bulletin for the week of December 1, 2025 included this CVE. Community coverage appeared across Linux security news outlets including LinuxSecurity.com, pro-linux.de, and linuxcompatible.org, reflecting broad awareness across the Linux ecosystem.