CVE-2026-74985 in Firefox
Summary
by MITRE • 08/18/2026
Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 154 and Firefox ESR 153.1.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 08/18/2026
The identified security flaw resides within the Enterprise Policies subsystem of Mozilla Firefox, representing a critical privilege escalation vector that allows lower-privileged processes or untrusted content to gain elevated system permissions. This vulnerability stems from an improper implementation of access control checks during the execution of policy-related operations, where the application fails to adequately verify whether the initiating context possesses the necessary administrative rights before granting access to sensitive configuration states or internal APIs. In enterprise environments, Firefox is often deployed with strict security policies managed by central administrators through JSON-based policy files. The flaw exploits a logic error in how these policies are parsed and applied, potentially allowing an attacker who has achieved code execution within a sandboxed tab or extension context to bypass standard isolation boundaries. By manipulating specific inputs sent to the Enterprise Policies handler, it is possible to trigger actions that modify browser settings, disable security features such as content blocking or HTTPS-only mode, or execute arbitrary commands with higher privileges than intended by the software's default security model.
From a technical perspective, this issue aligns closely with CWE-269, which classifies Improper Privilege Management vulnerabilities where an actor is able to perform actions without having been granted the proper permissions. The exploitation mechanism likely involves crafting malicious payloads that interact with the policy engine in ways that bypass validation routines, effectively tricking the browser into treating untrusted input as authoritative administrative directives. This type of flaw is particularly dangerous because it undermines the foundational trust model of web browsers, which rely on strict separation between user content and privileged system components. The vulnerability impacts the integrity and confidentiality of the browsing session by allowing attackers to alter security configurations at will, potentially disabling protections that safeguard against phishing, malware downloads, or data exfiltration attempts. Furthermore, in managed environments where Firefox is used as a corporate gateway for internet access, this flaw could be leveraged to establish persistent footholds within an organization's network perimeter if the browser process runs with elevated privileges relative to other applications.
The operational impact of this vulnerability extends beyond individual user compromise to affect organizational security postures significantly. Attackers can use this privilege escalation to disable telemetry reporting, preventing administrators from detecting suspicious activities or malware infections on affected endpoints. Additionally, by modifying enterprise policies, an attacker could redirect browser traffic through malicious proxies for man-in-the-middle attacks or inject custom extensions that monitor keystrokes and capture sensitive credentials stored within the browser profile. This capability effectively neutralizes many of the security controls implemented at the application level, leaving users vulnerable to subsequent exploitation stages such as credential harvesting or lateral movement within a networked environment. The severity is compounded by the fact that enterprise policies are often perceived as immutable rules enforced by IT departments, leading administrators and end-users alike to underestimate risks associated with browser-level configuration tampering.
To mitigate this risk, organizations must ensure that all instances of Firefox across their infrastructure are updated to version 154 for standard releases or version 153.1 for Extended Support Release channels immediately upon availability. Patching is the primary and most effective remediation strategy as it addresses the underlying code defects responsible for the improper privilege checks within the Enterprise Policies component. In addition to applying updates, administrators should review their current policy configurations to ensure that sensitive settings are not overly permissive or exposed to untrusted contexts unnecessarily. Implementing strict content security policies and restricting the execution of unsigned extensions can further reduce the attack surface available to potential exploiters. Regular auditing of browser logs for anomalous configuration changes is also recommended to detect any attempted exploitation activities before they result in full system compromise. Monitoring tools should be configured to alert on deviations from baseline policy states, providing an additional layer of defense against dynamic privilege escalation attempts that might evade static patching measures if applied inconsistently across endpoints.