CVE-2023-25362 in WebKitGTK
Summary
by MITRE • 03/02/2023
A use-after-free vulnerability in WebCore::RenderLayer::repaintBlockSelectionGaps in WebKitGTK before 2.36.8 allows attackers to execute code remotely.
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Analysis
by VulDB Data Team • 11/30/2025
The vulnerability identified as CVE-2023-25362 represents a critical use-after-free flaw within the WebKitGTK rendering engine that specifically affects the WebCore::RenderLayer::repaintBlockSelectionGaps function. This issue arises from improper memory management where freed memory locations are accessed after being deallocated, creating a potential attack surface for remote code execution. The vulnerability exists in WebKitGTK versions prior to 2.36.8, making all affected installations susceptible to exploitation by malicious actors who can craft specially crafted web content to trigger the flaw.
The technical implementation of this vulnerability stems from a memory management error in the rendering layer of the WebKit browser engine. When processing certain HTML content that involves block selection gaps, the WebCore::RenderLayer::repaintBlockSelectionGaps method fails to properly manage object lifecycles, resulting in a situation where memory that has been freed is subsequently accessed. This use-after-free condition occurs during the repainting process of rendered web content, specifically when handling selection gaps in block elements. The flaw demonstrates characteristics consistent with CWE-416, which defines use-after-free vulnerabilities as a condition where memory is accessed after it has been freed, and aligns with ATT&CK technique T1059.001 for remote code execution through browser exploitation.
The operational impact of this vulnerability is severe as it enables remote code execution without user interaction, making it particularly dangerous for web-based attacks. Attackers can leverage this vulnerability by hosting malicious web content that, when rendered by an affected WebKitGTK browser, triggers the memory corruption. The exploitability of this flaw is enhanced by the fact that it requires no user interaction beyond visiting a compromised website, making it a prime target for drive-by attacks. The memory corruption can potentially be leveraged to execute arbitrary code with the privileges of the browser process, which may lead to complete system compromise depending on the execution environment and user permissions.
Mitigation strategies for CVE-2023-25362 primarily focus on immediate patching of affected WebKitGTK installations to version 2.36.8 or later. System administrators should prioritize updating their WebKitGTK deployments across all affected platforms, particularly those running web browsers or applications that utilize the WebKitGTK rendering engine. Additionally, organizations should implement network-level protections including web application firewalls and content filtering systems that can detect and block malicious web content targeting this specific vulnerability. Browser vendors and distribution maintainers should also consider implementing additional runtime protections such as address space layout randomization and stack canaries to make exploitation more difficult. Security monitoring should include detection of anomalous browser behavior patterns that might indicate exploitation attempts, and incident response procedures should be updated to address potential compromise scenarios involving this memory corruption vulnerability.