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Mozilla released Firefox ESR 140.6 to address several high and moderate impact security vulnerabilities, including use-after-free, sandbox escape, privilege escalation, JIT miscompilation, and same-origin policy bypass issues. Notable vulnerabilities include CVE-2025-14321 (use-after-free in WebRTC: Signaling), CVE-2025-14322 (sandbox escape in Graphics: CanvasWebGL), and multiple privilege escalation flaws in the DOM: Notifications and Netmonitor components. Several JIT miscompilation bugs in the JavaScript Engine were also patched, which could potentially allow attackers to execute arbitrary code.
Additionally, memory safety bugs affecting previous versions of Firefox ESR, Thunderbird, and Firefox were resolved, with some showing evidence of memory corruption that could be exploited. Mozilla recommends updating to Firefox ESR 140.6 to mitigate these risks and ensure systems are protected against these vulnerabilities.
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Mozilla published advisory MFSA 2025-94 for Firefox ESR 140.6, disclosing that security vulnerabilities were fixed in the release. The two references describe the same advisory and represent a single event.
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Mozilla released Firefox 146, addressing a series of high-impact security vulnerabilities, including several use-after-free flaws, privilege escalation issues, and a sandbox escape. Notable vulnerabilities include `CVE-2025-14321` (use-after-free in WebRTC: Signaling), `CVE-2025-14322` (sandbox escape in Graphics: CanvasWebGL), and multiple privilege escalation bugs in components such as DOM: Notifications and Netmonitor. Several JIT miscompilation vulnerabilities in the JavaScript Engine were also patched, along with a same-origin policy bypass and spoofing issue in the Downloads Panel. The update also resolves memory safety bugs affecting both Firefox and Thunderbird, some of which could potentially be exploited for remote code execution. Mozilla rates the overall impact of these vulnerabilities as high, urging users to update to Firefox 146 promptly to mitigate risk. The advisories provide CVE identifiers and reference associated bug reports for further technical details.
Jun 29, 2026
Multiple critical vulnerabilities were identified in Mozilla Firefox and Firefox ESR, with the most severe enabling arbitrary code execution. Affected versions include Firefox prior to 146, Firefox ESR prior to 115.31, and Firefox ESR prior to 140.6. The vulnerabilities include use-after-free in WebRTC (`CVE-2025-14321`), sandbox escape in Graphics (`CVE-2025-14322`), privilege escalation in the DOM (`CVE-2025-14323`), JIT miscompilation in the JavaScript Engine (`CVE-2025-14324`, `CVE-2025-14325`), and multiple memory safety bugs. Exploitation could allow attackers to install programs, modify or delete data, or create new accounts with full user rights, depending on the privileges of the compromised user. There are currently no reports of these vulnerabilities being exploited in the wild. Security advisories from both the Canadian Centre for Cyber Security and the Multi-State Information Sharing and Analysis Center (MS-ISAC) urge users and administrators to apply the latest updates immediately to mitigate risk. The advisories highlight the importance of prompt patching, especially for large organizations and government entities, as the risk is assessed as high for these sectors. The updates address all known vulnerabilities, and users with fewer system privileges are less impacted than those with administrative rights.
Jun 29, 2026
Mozilla released **Firefox 147** with fixes for **16 security vulnerabilities**, including multiple **high-severity sandbox escape** issues and memory-safety flaws that could enable **arbitrary code execution** if exploited. Reported problem areas include the **Graphics** stack (notably WebGL/Canvas-related code paths), the **Messaging System**, IPC, and other core browser components; the fixes also apply to **Firefox ESR 140.7** and **Thunderbird ESR 140.7/147**, with vendors urging users to update promptly given ongoing browser-targeted attack activity. Public reporting highlights that several of the most serious issues involve bypassing Firefox’s isolation model via sandbox escapes in graphics and messaging components, alongside memory corruption bugs (including issues described as likely exploitable with sufficient effort). While no confirmed in-the-wild exploitation was reported in the coverage, the concentration of high-impact graphics-related vulnerabilities underscores continued risk in complex rendering surfaces such as **WebGL** and **Canvas**, reinforcing the need for rapid patch deployment across managed endpoints.
Jun 29, 2026