CVE-2026-121227 in Chrome
Summary
by MITRE • 11/03/2026
Uninitialized resource in Skia in Google Chrome prior to 157.0.8103.38 allowed a remote attacker who had compromised the renderer process to read memory outside the sandbox via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified as an uninitialized resource issue within the Skia graphics library, which is integrated into Google Chrome prior to version 157.0.8103.38, represents a critical failure in memory management during rendering operations. This flaw allows for out-of-bounds reads when specific graphical primitives are processed incorrectly by the browser engine. The root cause lies in the improper initialization of internal data structures or buffers within Skia before they are accessed for drawing commands. When an attacker crafts a malicious HTML page that triggers these specific code paths, the application fails to verify whether the memory regions being read have been properly allocated and initialized. This oversight results in the browser reading from arbitrary locations in the process memory space rather than the intended buffer boundaries.
From a technical perspective, this vulnerability falls under the category of improper initialization leading to information disclosure or potential further exploitation vectors. In terms of industry standards, this aligns with CWE-457, which describes the use of an uninitialized variable, and CWE-125, known as Out-of-bounds Read. The severity is classified as High by Chromium security teams because it directly impacts the integrity of the renderer process memory space. Although the attacker requires a compromised renderer process to trigger this condition effectively in many scenarios, the ability to read arbitrary memory can be leveraged to extract sensitive data such as cookies, session tokens, or cryptographic keys stored within that address space. This constitutes a significant breach of confidentiality for users interacting with malicious content.
The operational impact is particularly severe due to its interaction with Chrome's multi-process architecture and sandboxing mechanisms. While the renderer process operates in a restricted environment designed to limit damage from web-based attacks, an out-of-bounds read can leak information that resides within the same process but outside the strict bounds of the allocated object. If the attacker has already achieved code execution or memory corruption via other means, this vulnerability serves as a powerful primitive for data exfiltration. It undermines the isolation guarantees provided by the sandbox because it allows reading sensitive state without necessarily triggering immediate crashes, which might alert security monitoring systems. The ability to read outside the intended buffer can also aid in bypassing address space layout randomization protections if combined with other techniques that leak memory addresses.
Mitigation strategies primarily involve updating Google Chrome to version 157.0.8103.38 or later, where these initialization checks have been corrected and bounds validation has been strengthened within the Skia library. For organizations unable to patch immediately, deploying strict content security policies can help mitigate some risks by restricting inline scripts and untrusted resources that might attempt to exploit this flaw. Additionally, enabling sandboxing features such as site isolation ensures that even if a renderer is compromised, the scope of accessible memory remains limited to specific sites rather than global process memory. Security teams should also monitor for anomalous network traffic patterns indicative of data exfiltration following visits to untrusted web pages, although detection at this stage may be challenging given the subtle nature of out-of-bounds reads that do not cause immediate application crashes.