CVE-2026-109706 in Firefox
Summary
by MITRE • 10/13/2026
Use-after-free in the Storage: IndexedDB component. This vulnerability was fixed in Firefox 158, Firefox ESR 115.43, and Firefox ESR 153.5.
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Analysis
by VulDB Data Team • 10/13/2026
The identified vulnerability represents a critical memory management error within Mozilla Firefox's storage subsystem, specifically affecting the IndexedDB component which is responsible for client-side structured data storage in web applications. This flaw manifests as an use-after-free condition, a severe class of software defects where a program continues to use a pointer after it has been freed from its allocated memory block. In the context of browser engines and their associated APIs like IndexedDB, such errors are particularly dangerous because they can lead to arbitrary code execution with the privileges of the user running the application. The vulnerability was addressed in Firefox version 158 as well as specific maintenance releases for Extended Support Release channels including ESR 115.43 and ESR 153.5, indicating that older or unpatched versions remain susceptible to exploitation by malicious web content designed to trigger this memory corruption state.
From a technical perspective, the root cause lies in improper handling of object lifecycles within the IndexedDB implementation. When an application interacts with indexed databases through JavaScript APIs, the browser engine manages internal data structures and pointers that reference these objects. If the underlying storage mechanism releases or deallocates memory associated with a database transaction or cursor while other parts of the system still hold references to that same memory region, accessing those stale pointers results in undefined behavior. This typically allows an attacker who controls the content of a webpage to manipulate heap contents, potentially overwriting function pointers or object vtables. Such manipulation can redirect execution flow to malicious shellcode injected into the browser process, thereby achieving remote code execution without any user interaction beyond visiting a crafted website.
The operational impact of this vulnerability is significant due to its potential for privilege escalation and data exfiltration. An attacker could exploit this flaw to bypass security controls such as the same-origin policy, gaining access to sensitive information stored locally by web applications or executing arbitrary commands on the victim's machine. This poses a direct threat to user privacy and system integrity, especially in enterprise environments where Firefox is deployed with specific configurations for handling corporate data. The existence of fixes in ESR channels highlights that even stable, long-term support versions are not immune to such high-severity issues if they remain unpatched, necessitating strict update policies across organizational fleets.
This vulnerability aligns closely with Common Weakness Enumeration identifier CWE-416 which describes use-after-free conditions as a category of memory corruption vulnerabilities. Furthermore, the exploitation technique falls under MITRE ATT&CK tactic T1203 involving software exploitation for initial access or privilege escalation. To mitigate this risk, organizations must ensure that all instances of Firefox are updated to at least version 158 or the corresponding ESR patches mentioned above. Additionally, implementing content security policies and restricting execution of untrusted scripts can reduce the attack surface by limiting the ability of malicious web pages to interact with IndexedDB in ways that might trigger this specific memory error. Regular patch management cycles should be enforced to close these gaps promptly as new vulnerabilities are disclosed and patched upstream.