CVE-2017-7785 in Firefox
Summary
by MITRE
A buffer overflow can occur when manipulating Accessible Rich Internet Applications (ARIA) attributes within the DOM. This results in a potentially exploitable crash. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.
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Analysis
by VulDB Data Team • 11/26/2025
The vulnerability identified as CVE-2017-7785 represents a critical buffer overflow condition that manifests within the handling of Accessible Rich Internet Applications ARIA attributes in web browsers. This flaw exists in the core DOM manipulation mechanisms of affected browser implementations, specifically within how they process and manage accessibility attributes that are essential for web application interoperability with assistive technologies. The issue stems from insufficient bounds checking when processing ARIA attribute data structures, creating opportunities for malicious input to exceed allocated memory buffers and potentially trigger arbitrary code execution through controlled memory corruption.
The technical exploitation of this vulnerability occurs during the parsing and manipulation of ARIA attributes within the Document Object Model, where attackers can craft malicious web content containing oversized or malformed ARIA attribute values. This buffer overflow condition typically manifests when browsers attempt to process accessibility metadata associated with web elements, particularly when these attributes contain excessive data beyond the expected buffer boundaries. The flaw is classified under CWE-121 as a stack-based buffer overflow, which occurs when data is written beyond the bounds of a fixed-length buffer, potentially overwriting adjacent memory locations including return addresses and critical program state information.
The operational impact of this vulnerability extends across multiple browser implementations and affects users of Firefox ESR 52.2 and earlier versions, Firefox 54 and earlier, as well as Thunderbird versions prior to 52.3. Attackers can leverage this vulnerability through malicious web pages or compromised websites that contain crafted ARIA attributes designed to trigger the buffer overflow condition during normal browser operation. The crash behavior resulting from this vulnerability can be exploited to achieve remote code execution, making it particularly dangerous in targeted attack scenarios where adversaries seek to compromise user systems through web-based delivery mechanisms. This vulnerability aligns with ATT&CK technique T1203 by enabling adversaries to gain system access through browser exploitation.
Mitigation strategies for CVE-2017-7785 require immediate patching of affected browser versions to the latest stable releases that include memory safety improvements and enhanced bounds checking for ARIA attribute processing. Organizations should implement browser hardening measures including disabling unnecessary accessibility features when not required, implementing content security policies to limit script execution from untrusted sources, and deploying web application firewalls that can detect and block malicious ARIA attribute patterns. Additionally, users should be educated about the risks of visiting untrusted websites and the importance of keeping browser software updated. Security monitoring should focus on detecting unusual browser crash patterns and memory access violations that may indicate exploitation attempts. The vulnerability demonstrates the critical importance of input validation in web browser security architectures, particularly for accessibility-related features that are often overlooked in traditional security assessments but represent significant attack surfaces when improperly implemented.