Mozilla has released Firefox 141 with significant security patches addressing 17 vulnerabilities, including several high-impact flaws that could potentially allow arbitrary code execution.
The Mozilla Foundation Security Advisory 2025-56, announced on July 22, 2025, details critical issues affecting the JavaScript engine, WebAssembly implementation, and various browser security mechanisms that require immediate attention from users and developers.
Critical JavaScript Engine Vulnerabilities Patched
The most severe vulnerabilities in this release target Firefox’s core JavaScript execution engines.
CVE-2025-8027 represents a critical flaw where IonMonkey-JIT only wrote 32 bits of a 64-bit return value to the stack on 64-bit platforms, while Baseline-JIT attempted to read the entire 64 bits, creating a dangerous memory inconsistency.
This vulnerability, discovered by researcher Nan Wang, could potentially be exploited for code execution through careful manipulation of JavaScript return values.
Additionally, CVE-2025-8028 affects ARM64 systems running WebAssembly code, where a br_table instruction with numerous entries could cause label truncation and incorrect branch address computation.
This flaw, reported by Gary Kwong, demonstrates the complexity of modern browser architectures where assembly-level optimizations can introduce security risks.
The vulnerability specifically targets WebAssembly’s branching mechanisms, which are crucial for performance in web applications running compiled code.
Security Bypasses and Browser Exploits
Several moderate-impact vulnerabilities expose fundamental security model bypasses in Firefox’s implementation.
CVE-2025-8036 allows attackers to circumvent Cross-Origin Resource Sharing (CORS) protections through DNS rebinding attacks, as Firefox cached CORS preflight responses across IP address changes.
This vulnerability, discovered by Viktor Bocz, undermines one of the web’s primary security boundaries between different origins.
The browser’s Content Security Policy (CSP) implementation also suffered from multiple weaknesses.
CVE-2025-8032 enables XSLT documents to bypass CSP restrictions by incorrectly propagating source document context, while CVE-2025-8031 exposes HTTP Basic Authentication credentials in CSP reports due to improper URL sanitization.
These flaws demonstrate how complex web standards can create unexpected attack vectors when implementation details are overlooked.
Memory Safety and Patch Implementation
Mozilla addressed multiple memory safety vulnerabilities through comprehensive patches affecting both Firefox and Thunderbird.
CVE-2025-8044, CVE-2025-8034, CVE-2025-8040, and CVE-2025-8035 represent clusters of memory corruption bugs that the Mozilla Fuzzing Team and security researchers identified across different browser versions.
These vulnerabilities showed evidence of memory corruption that could potentially be exploited for arbitrary code execution with sufficient effort.
The security update also addresses platform-specific issues, including CVE-2025-8041 and CVE-2025-8042 affecting Firefox for Android, where URL truncation prioritized aesthetics over security visibility and sandboxed iframes could inappropriately initiate downloads.
These mobile-specific vulnerabilities highlight the additional complexity of maintaining security across diverse platforms and form factors in modern browser development.
Find this Story Interesting! Follow us on LinkedIn and X to Get More Instant Updates.
%20(1).webp?resize=1600,900&ssl=1&description=The Mozilla Foundation Security Advisory 2025-56, announced on July 22, 2025, details critical issues affecting the JavaScript engine,){kind=link}