CVE-2026-2782 is a privilege escalation vulnerability identified in the Netmonitor component of Mozilla Firefox, affecting all versions prior to 148 and Firefox ESR versions prior to 140.8. The Netmonitor component is part of Firefox's developer tools, primarily used for network traffic inspection and debugging. The vulnerability allows an attacker to escalate privileges within the browser environment, potentially bypassing security restrictions and gaining unauthorized access to sensitive browser functions or data. Although specific technical details of the flaw are not disclosed, privilege escalation typically involves exploiting improper access control or sandbox escape mechanisms. The vulnerability was reserved on February 19, 2026, and published on February 24, 2026, but no CVSS score or patch has been released yet. No known exploits are currently reported in the wild, suggesting limited active exploitation. However, the affected Firefox versions are widely deployed across consumer and enterprise environments, including the ESR branch favored for stability and long-term support. The lack of a patch means users remain vulnerable until updates are issued. Attackers with local access or the ability to trick users into executing malicious content within the browser could leverage this flaw to gain elevated privileges, potentially leading to further compromise of user data or system integrity. The vulnerability's impact spans confidentiality, integrity, and potentially availability if exploited to execute arbitrary code or disrupt browser operations.

The primary impact of CVE-2026-2782 is unauthorized privilege escalation within the Firefox browser, which can lead to significant security breaches. Attackers exploiting this vulnerability could bypass browser sandboxing and security controls, gaining access to sensitive information such as stored credentials, browsing history, or session tokens. This could facilitate further attacks like credential theft, session hijacking, or persistent malware installation. For organizations, especially those using Firefox ESR in enterprise environments, this vulnerability poses risks to data confidentiality and integrity. It could also undermine trust in secure browsing, potentially exposing internal resources if Firefox is used to access corporate networks. Although no known exploits exist yet, the vulnerability's presence in widely used browser versions increases the risk of future exploitation. The lack of a patch prolongs exposure, and attackers may develop exploits targeting this flaw. Overall, the vulnerability could lead to significant operational and reputational damage if exploited at scale.

Organizations and users should monitor Mozilla's official channels for the release of security patches addressing CVE-2026-2782 and apply updates promptly once available. Until a patch is released, consider the following mitigations: restrict access to developer tools including Netmonitor to trusted users only, disable or limit the use of developer tools in managed environments, and enforce strict browser usage policies to prevent execution of untrusted scripts or extensions. Employ endpoint security solutions capable of detecting anomalous browser behavior indicative of privilege escalation attempts. Additionally, educate users about the risks of interacting with suspicious web content or downloading untrusted files. For enterprises, consider deploying browser isolation technologies or sandboxing at the OS level to contain potential exploitation. Regularly audit browser configurations and extensions to minimize attack surface. Finally, maintain robust network segmentation and monitoring to detect lateral movement in case of compromise.