Description

Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, and Firefox ESR 153.3.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-09-15T13:16:48.593Z",
  "pubdate": "2026-09-15T13:16:48.593Z",
  "executiveSummary": "A critical security vulnerability has been identified within the Graphics: CanvasWebGL component, facilitating local privilege escalation. The flaw originates from improper handling of boundary conditions during memory operations within the WebGL graphics pipeline.\nThe vulnerability affects Firefox, Firefox ESR 115.41, Firefox ESR 140.16, and Firefox ESR 153.3. By exploiting this defect, an attacker can bypass standard security constraints, potentially achieving unauthorized execution with elevated privileges on the host system.\nSuccessful exploitation requires the victim to interact with malicious web content that triggers the flawed boundary condition, allowing the attacker to manipulate memory state within the browser's graphics rendering process.\nThe risk implication is severe, as it grants an adversary the ability to transcend the browser sandbox. No user interaction beyond navigating to a malicious URI is strictly necessary once the exploit is staged. Organizations should prioritize updating to the patched versions immediately to neutralize this vector of attack.",
  "technicalDetails": "The vulnerability resides within the Graphics: CanvasWebGL component, specifically concerning the validation logic applied to boundary conditions during buffer manipulation and state synchronization. In WebGL, the browser must rigorously validate parameters passed to low-level graphics APIs to ensure memory safety. The root cause of this vulnerability is an insufficient check on inputs provided to the Graphics: CanvasWebGL component, which leads to an out-of-bounds access condition.\nWhen an attacker provides specially crafted commands via the WebGL API, the component fails to correctly verify the bounds of memory buffers or index offsets. This failure allows for an out-of-bounds read or write operation within the memory space allocated to the graphics process. By precisely grooming the heap or utilizing techniques such as heap spray, an attacker can leverage this primitive to overwrite sensitive memory structures, such as function pointers or object vtables.\nThe attack flow commences when a user visits a malicious website containing a crafted WebGL shader or a series of malicious GL commands. The attacker triggers the boundary condition error, forcing the component to perform an operation outside the intended memory region. By overwriting internal control data, the attacker redirects execution flow to a payload crafted to execute arbitrary code with the privileges of the browser's graphics process.\nGiven that the graphics process often operates with distinct hardware access rights and memory visibility, successful exploitation can lead to a sandbox escape. Once the initial primitive is established, the attacker may pivot to kernel-level exploitation if additional system-specific vulnerabilities are accessible via the compromised process. The exploitation does not require prior authentication, as it leverages the inherent functionality of the browser's WebGL implementation to facilitate the memory corruption.\nAffected versions include Firefox 156 and specific ESR releases: 115.41, 140.16, and 153.3. The vulnerability is triggered remotely through standard browser interaction, and the lack of robust bounds checking within the graphics pipeline allows for the circumvention of memory isolation mechanisms, resulting in potential full system compromise if post-exploitation privileges are leveraged effectively."
}