CVE-2025-11756: 
vulnerability analysis and mitigation

CVE-2025-11756 is a use-after-free vulnerability in the Safe Browsing component of Google Chrome that allows a remote attacker who has already compromised the renderer process to potentially perform out-of-bounds memory access via a crafted HTML page. It affects all versions of Google Chrome prior to 141.0.7390.107 on Windows, macOS, and Linux, as well as Microsoft Edge (Chromium-based). The vulnerability was reported by researcher "asnine" on 2025-09-25 and patched on October 14, 2025, with NVD publication on November 6, 2025. It carries a CVSS v3.1 base score of 8.8 (High), assessed by CISA-ADP (Chrome Release, Microsoft MSRC).

The vulnerability is classified as CWE-416 (Use After Free), occurring within Chrome's Safe Browsing component in the renderer process. A use-after-free condition arises when memory that has been freed is subsequently accessed, potentially allowing an attacker to corrupt heap memory and redirect code execution. Exploitation requires the attacker to have already compromised the renderer process — meaning this is a post-renderer-compromise escalation primitive — and then deliver a specially crafted HTML page to trigger the vulnerable code path. The Chromium issue tracker entry (ID 447192722) is restricted pending broad user patching (Chrome Release).

Successful exploitation can result in high impact to confidentiality, integrity, and availability of the affected system, potentially enabling arbitrary code execution within the browser process. An attacker who has already achieved renderer compromise could leverage this vulnerability to escape sandbox boundaries or perform unauthorized out-of-bounds memory reads/writes, threatening sensitive user data and system integrity. The scope is limited to the browser process itself, but combined with a renderer exploit, this could form part of a full browser sandbox escape chain (Chrome Release, Microsoft MSRC).

No public proof-of-concept exploit code has been confirmed, though exploitation has been reported by various sources including a blog post on code.blog framing it as an enterprise-critical RCE threat (Feedly). The vulnerability is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.036%, indicating a relatively low probability of widespread exploitation in the near term. No specific threat actor attribution has been reported. Detection signatures are available from Qualys and Tenable Nessus (Feedly).

1. Renderer Compromise (Prerequisite): The attacker must first compromise the Chrome renderer process, typically via a separate vulnerability (e.g., a JavaScript engine bug or another renderer-level flaw), by luring the victim to a malicious or attacker-controlled webpage.
2. Craft Malicious HTML Page: The attacker prepares a specially crafted HTML page designed to trigger the use-after-free condition in Chrome's Safe Browsing component, manipulating memory allocation and deallocation sequences.
3. Trigger Use-After-Free: When the victim's browser (running a version prior to 141.0.7390.107) loads the crafted page, the Safe Browsing component accesses a previously freed memory object, causing a use-after-free condition.
4. Out-of-Bounds Memory Access: The attacker exploits the freed memory region — potentially having placed controlled data there via heap grooming — to achieve out-of-bounds memory reads or writes.
5. Achieve Code Execution / Escalation: By controlling the freed memory contents, the attacker redirects execution flow, potentially escaping the renderer sandbox or executing arbitrary code at a higher privilege level within the browser process (Chrome Release).

• Network: Unexpected outbound connections from the browser process to unknown or suspicious IP addresses following visits to unfamiliar websites; unusual DNS lookups initiated by the Chrome process.
• Process: Chrome renderer processes (chrome.exe / chrome on Linux/macOS) spawning unexpected child processes such as command shells (cmd.exe, /bin/bash) or network utilities (curl, wget, powershell).
• Logs: Browser crash reports or crash dumps referencing the Safe Browsing component; AddressSanitizer or heap corruption error logs if instrumented builds are in use.
• File System: Unexpected files written to user profile directories or temporary folders by the Chrome process; new scheduled tasks or persistence mechanisms created shortly after browser activity.

Google released the fix in Chrome stable channel version 141.0.7390.107 (Linux) and 141.0.7390.107/.108 (Windows/Mac), published October 14, 2025. Microsoft also released a corresponding patch for Microsoft Edge (Chromium-based) via the MSRC update guide. Users and administrators should immediately update Chrome to version 141.0.7390.107 or later and enable automatic updates. As a supplementary measure, organizations should enforce web filtering policies, use browser sandboxing technologies, and monitor for suspicious browser process behavior (Chrome Release, Microsoft MSRC).

The vulnerability received broad coverage from security news outlets including CyberSecurityNews, GBHackers, The Cyber Express, eSecurity Planet, and Heise, with most framing it as a high-severity browser threat requiring prompt patching. A blog post on code.blog characterized it as an "emergency RCE" and the "#1 enterprise threat," urging CISOs to prioritize fleet-wide patching verification. Security community members on Mastodon (infosec.exchange) and Bluesky also flagged the advisory shortly after disclosure. The Hacker News included it in their weekly security recap for the week of October 19, 2025.