CVE-2019-7581 in libming
Summary
by MITRE
The parseSWF_ACTIONRECORD function in util/parser.c in libming through 0.4.8 allows remote attackers to have unspecified impact via a crafted swf file that triggers a memory allocation failure, a different vulnerability than CVE-2018-7876.
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Analysis
by VulDB Data Team • 09/08/2025
The vulnerability identified as CVE-2019-7581 affects libming version 0.4.8 and earlier, specifically within the parseSWF_ACTIONRECORD function located in util/parser.c. This issue represents a memory allocation failure that occurs when processing specially crafted swf files, creating a potential remote code execution or denial of service scenario. The vulnerability is distinct from CVE-2018-7876, indicating a separate code path or memory handling mechanism that can be exploited through malformed flash content. The affected library serves as a utility for parsing and manipulating flash files, making it a critical component in systems that process or convert swf content. When a malicious swf file triggers the memory allocation failure, the consequences can range from application crashes to more severe system compromise depending on the execution context and memory corruption patterns. The vulnerability demonstrates a classic memory safety issue where improper handling of input data leads to allocation failures that can be leveraged by remote attackers to disrupt service availability or potentially execute arbitrary code.
The technical flaw stems from inadequate input validation and memory management within the parseSWF_ACTIONRECORD function, which processes action record data structures found in swf files. When the parser encounters malformed or crafted action records, it fails to properly manage memory allocation requests, leading to potential heap corruption or allocation failures that can be exploited remotely. This type of vulnerability aligns with CWE-122, heap-based buffer overflow, and CWE-704, incorrect type conversion or cast, as the parser likely performs operations that assume valid data structures without proper validation. The function's handling of action records, which are fundamental components of swf file format, suggests that attackers can manipulate the action record headers or data to cause unexpected memory allocation behavior. The vulnerability operates at the parsing layer where untrusted input is processed without sufficient safeguards, making it a prime target for exploitation through carefully crafted swf files that trigger the problematic code path.
The operational impact of CVE-2019-7581 extends beyond simple denial of service scenarios, as memory allocation failures in parsing libraries can lead to system instability and potential privilege escalation depending on the execution environment. Systems that rely on libming for swf processing, including web applications, content management systems, or media processing servers, become vulnerable to remote attacks that can cause service disruption or compromise. The vulnerability is particularly concerning because swf files are commonly encountered in web environments and can be delivered through various attack vectors including malicious websites, email attachments, or file sharing platforms. When exploited, the vulnerability can cause applications to crash or behave unpredictably, potentially allowing attackers to gain unauthorized access to system resources or execute malicious code. The impact is amplified in environments where libming is used as a library component in larger applications, as the failure can propagate through the application stack and affect multiple system components.
Mitigation strategies for CVE-2019-7581 should focus on immediate patching of libming to version 0.4.9 or later, where the memory allocation handling has been corrected. Organizations should implement strict input validation for all swf file processing, including content filtering and sandboxing mechanisms to isolate parsing operations from core system functions. Network-level defenses should include web application firewalls that can detect and block suspicious swf file content, particularly those containing malformed action records. The implementation of memory safety checks and bounds validation within the parsing functions should be enforced to prevent allocation failures from occurring. Additionally, system administrators should monitor for any signs of exploitation attempts through log analysis and intrusion detection systems. The vulnerability highlights the importance of maintaining up-to-date libraries and implementing defense-in-depth strategies, as the issue falls under ATT&CK technique T1203, Exploitation for Client Execution, and T1059, Command and Scripting Interpreter, through the potential for remote code execution. Regular security assessments and vulnerability scanning should be conducted to identify similar memory safety issues in other parsing libraries and system components that may be susceptible to similar exploitation patterns.