# Mozilla Patches Dozens of Firefox Flaws

Published: 2026-05-20 · Severity: medium
Canonical: https://vorant.io/reports/78d86372-22dd-52b8-a1b0-55b7ce55c2a5/mozilla-patches-dozens-of-firefox-flaws

> Mozilla fixed multiple vulnerabilities in Firefox and Firefox ESR, some allowing arbitrary code execution, with no known exploitation in the wild.

Mozilla has released updates addressing a large batch of vulnerabilities across Firefox, Firefox for iOS, and Firefox ESR, several of which are rated as high severity and could lead to arbitrary code execution if exploited. The most serious issues stem from memory safety bugs, use-after-free conditions, sandbox escapes, and same-origin policy bypasses across components including the JavaScript Engine, DOM, Audio/Video, and Profile Backup. Successful exploitation could allow an attacker to install programs, manipulate or delete data, or create new accounts, with impact scaled by the privileges of the logged-in user.

The advisory also lists numerous lower-severity issues including information disclosure, spoofing, privilege escalation, and denial-of-service bugs affecting components such as WebRTC, Networking, Enterprise Policies, and WebExtensions. There are currently no reports of in-the-wild exploitation for any of these vulnerabilities. MS-ISAC recommends organizations apply Mozilla's updates promptly following standard patch management and testing procedures, and reinforces standard mitigations such as least-privilege enforcement, browser allowlisting, and exploit protection features.

## Mentioned in this report

- Vulnerabilities: CVE-2026-8388, CVE-2026-8391, CVE-2026-8401, CVE-2026-8706, CVE-2026-8945, CVE-2026-8946, CVE-2026-8947, CVE-2026-8948, CVE-2026-8949, CVE-2026-8950, CVE-2026-8951, CVE-2026-8952, CVE-2026-8953, CVE-2026-8954, CVE-2026-8955, CVE-2026-8956, CVE-2026-8957, CVE-2026-8958, CVE-2026-8959, CVE-2026-8960, CVE-2026-8961, CVE-2026-8962, CVE-2026-8963, CVE-2026-8964, CVE-2026-8965, CVE-2026-8966, CVE-2026-8967, CVE-2026-8968, CVE-2026-8969, CVE-2026-8970, CVE-2026-8971, CVE-2026-8972, CVE-2026-8973, CVE-2026-8974, CVE-2026-8975

Source reporting: https://www.cisecurity.org/advisory/multiple-vulnerabilities-in-mozilla-products-could-allow-for-arbitrary-code-execution_2026-052

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