CVE-2023-4050 in Firefox
Summary
by MITRE • 08/01/2023
In some cases, an untrusted input stream was copied to a stack buffer without checking its size. This resulted in a potentially exploitable crash which could have led to a sandbox escape. This vulnerability affects Firefox < 116, Firefox ESR < 102.14, and Firefox ESR < 115.1.
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Analysis
by VulDB Data Team • 06/20/2025
This vulnerability represents a classic stack buffer overflow condition that emerged in Mozilla Firefox's handling of untrusted input streams. The flaw occurs when the application processes data from external sources without proper size validation before copying it into a fixed-size stack buffer. This type of vulnerability falls under the common weakness enumeration CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent stack memory. The vulnerability affects multiple Firefox versions including Firefox 115 and earlier, Firefox ESR 102.13 and earlier, and Firefox ESR 115.0 and earlier, indicating a widespread impact across both regular and extended support release channels.
The technical implementation of this vulnerability stems from the application's failure to validate input stream dimensions before performing memory operations. When an attacker can control the size of input data and that data exceeds the allocated stack buffer capacity, the excess data overflows into adjacent memory locations. This overflow can corrupt stack canaries, return addresses, or other critical execution metadata that is essential for proper program flow control. The exploitation potential is particularly concerning because it could enable sandbox escape scenarios, where an attacker might leverage the overflow to bypass security boundaries that normally isolate untrusted code execution from the underlying operating system. This aligns with attack techniques described in the attack pattern taxonomy under ATT&CK T1055 for process injection and T1070 for indicator removal.
The operational impact of this vulnerability extends beyond simple crash conditions to potentially enable more sophisticated attacks. While the primary effect manifests as a potentially exploitable crash, the nature of stack buffer overflows in modern applications often provides attackers with opportunities to achieve arbitrary code execution or information disclosure. The sandbox escape capability means that an attacker who successfully exploits this vulnerability could potentially gain access to system resources or sensitive data that would normally be protected by Firefox's security model. The affected versions represent a significant portion of the user base, making this vulnerability particularly dangerous in practice. The vulnerability's presence in both regular and extended support releases indicates that the flaw was not adequately addressed in the security patches for older versions, leaving organizations with legacy deployments at risk.
Mitigation strategies for this vulnerability should prioritize immediate patching of all affected Firefox versions to the latest security releases. Organizations should implement network monitoring to detect potential exploitation attempts and establish incident response procedures for handling suspected compromise. Additional protective measures include implementing strict input validation policies, deploying web application firewalls, and utilizing sandboxing technologies to limit the impact of potential exploitation. Security teams should also consider implementing automated vulnerability scanning to identify systems running unsupported Firefox versions and establish baseline configurations that enforce proper buffer size validation. The remediation approach should align with industry best practices for memory safety and follow the principle of least privilege to minimize the potential damage from successful exploitation attempts.