CVE-2023-4048 in Firefox
Summary
by MITRE • 08/01/2023
An out-of-bounds read could have led to an exploitable crash when parsing HTML with DOMParser in low memory situations. This vulnerability affects Firefox < 116, Firefox ESR < 102.14, and Firefox ESR < 115.1.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 06/20/2025
This vulnerability represents a critical memory safety issue within Mozilla Firefox's HTML parsing engine that could potentially lead to arbitrary code execution. The flaw manifests specifically when the DOMParser API processes malformed HTML content under constrained memory conditions, creating an out-of-bounds read condition that adversaries could exploit to crash the browser or potentially execute malicious code. The vulnerability stems from insufficient bounds checking during HTML document parsing operations, particularly when the parser encounters edge cases in document structure or memory allocation patterns that trigger unexpected behavior in the underlying memory management systems.
The technical implementation of this vulnerability involves the DOMParser's handling of HTML content where memory allocation and deallocation sequences create opportunities for out-of-bounds memory access. When Firefox processes HTML documents with specific malformed structures under low memory scenarios, the parser fails to properly validate memory boundaries during parsing operations, leading to memory corruption that can be leveraged by attackers. This issue falls under the common weakness enumeration CWE-125 which specifically addresses out-of-bounds read vulnerabilities, and it aligns with ATT&CK technique T1059.007 for application execution through web-based attack vectors. The vulnerability's exploitation potential is heightened by the fact that it occurs during routine HTML parsing operations that are fundamental to web browsing, making it particularly dangerous in real-world scenarios.
The operational impact of this vulnerability extends beyond simple browser crashes to potentially enable remote code execution attacks against unsuspecting users. Attackers could craft malicious web pages containing specially formatted HTML content that triggers the out-of-bounds read condition when processed by affected Firefox versions. This creates a significant risk for users who browse untrusted websites or receive malicious web content through various attack vectors including phishing, drive-by downloads, or compromised websites. The vulnerability affects not just regular Firefox releases but also extended support releases, meaning organizations using older Firefox versions for enterprise environments remain at risk. The memory constraint aspect of this vulnerability suggests that it may be more easily triggered in resource-constrained environments or when multiple browser tabs are open simultaneously, making it particularly relevant for mobile devices or systems with limited memory resources.
Mitigation strategies for this vulnerability primarily involve immediate software updates to patched versions of Firefox, specifically version 116 for regular releases and 102.14 or 115.1 for extended support releases. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly, as the vulnerability's exploitation potential makes it a high-priority security concern. Additional defensive measures include implementing web content filtering solutions, enabling sandboxing features within Firefox, and monitoring for suspicious web activity that might indicate exploitation attempts. Security teams should also consider deploying intrusion detection systems that can identify patterns associated with exploitation attempts targeting this specific vulnerability, as the out-of-bounds read behavior creates detectable network and system artifacts that can be monitored for potential attacks. The vulnerability's nature also suggests that browser hardening measures such as disabling unnecessary JavaScript features or restricting DOMParser usage in sensitive contexts could provide additional layers of protection against exploitation attempts.