CVE-2026-87630 in Chrome
Summary
by MITRE • 09/09/2026
Integer overflow in WebRTC in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to read memory inside the sandbox via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as an integer overflow within the WebRTC implementation of Google Chrome, specifically in versions prior to 153.0.8010.36, represents a critical memory safety flaw that undermines the browser's sandboxing mechanisms. This defect arises from improper handling of arithmetic operations during the processing of media streams or signaling data associated with real-time communication protocols. When an attacker crafts a malicious HTML page containing specially designed WebRTC payloads, they can trigger conditions where numerical values exceed their allocated storage capacity. Instead of throwing an exception or clamping the value to a safe maximum, the system wraps around due to standard integer arithmetic behavior in lower-level languages like C++. This wrap-around effect results in significantly smaller buffer sizes being allocated than intended by the application logic, creating a discrepancy between the expected and actual memory boundaries.
The operational impact of this vulnerability is severe because it facilitates an out-of-bounds read operation within the browser's sandboxed environment. By exploiting the miscalculated buffer size, a remote attacker can cause the WebRTC component to access memory locations that lie outside the legitimate bounds of the allocated data structure. This unauthorized memory access allows the extraction of sensitive information stored in adjacent memory regions, which may include cryptographic keys, session tokens, or other private user data. The ability to read arbitrary memory from within the sandbox effectively neutralizes a primary defense mechanism designed to isolate web content from the underlying operating system and other browser processes. Consequently, this flaw enables privilege escalation scenarios where an attacker can pivot from simple code execution in a low-privilege context to gaining access to higher-security contexts or sensitive data stores that were previously protected by isolation boundaries.
From a classification perspective, this vulnerability aligns with CWE-190, which defines integer overflow or wraparound when performing arithmetic operations. The exploitation technique leverages the resulting memory corruption to achieve information disclosure, mapping closely to CWE-125, out-of-bounds read. In terms of offensive security frameworks such as MITRE ATT&CK, this vulnerability supports techniques related to Tactic TA0006, Credential Access, specifically through methods like Steal Web Session Cookie or Unsecured Credentials if sensitive data is exposed. Furthermore, the exploitation vector falls under Initial Access via User Execution, where a victim must be induced to visit a crafted webpage, often facilitated by social engineering tactics that lure users into interacting with malicious content disguised as legitimate media streams or communication requests.
Mitigation strategies for this vulnerability primarily involve updating Google Chrome to version 153.0.8010.36 or later, where the underlying arithmetic checks have been corrected to prevent integer wraparounds and enforce strict bounds checking on buffer allocations. For organizations unable to patch immediately, deploying web content security policies that restrict WebRTC functionality can reduce the attack surface. Additionally, enabling advanced sandboxing features such as site isolation ensures that even if a vulnerability is exploited in one process, the impact is contained within that specific context, limiting the ability of an attacker to access memory from other sites or sensitive browser components. Continuous monitoring for anomalous network traffic patterns associated with WebRTC connections and restricting permissions for third-party scripts can also provide layers of defense against exploitation attempts targeting this class of vulnerabilities.