CVE-2023-29950 in swfrender
Summary
by MITRE • 04/27/2023
swfrender v0.9.2 was discovered to contain a heap buffer overflow in the function enumerateUsedIDs_fillstyle at modules/swftools.c
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Analysis
by VulDB Data Team • 12/16/2025
The vulnerability CVE-2023-29950 represents a critical heap buffer overflow condition within swfrender version 0.9.2, specifically within the enumerateUsedIDs_fillstyle function located in the modules/swftools.c source file. This flaw emerges during the processing of flash media files and affects the software's ability to properly handle memory allocation when enumerating used identifiers within fill style operations. The buffer overflow occurs when the application attempts to write data beyond the allocated memory boundaries, creating potential avenues for memory corruption and arbitrary code execution. This vulnerability directly impacts the software's security posture and represents a significant risk to systems processing flash content.
The technical implementation of this vulnerability stems from inadequate bounds checking within the enumerateUsedIDs_fillstyle function, which processes fill style information from swf files during rendering operations. When the application encounters specific malformed input data within fill style sections, it fails to validate the size of data being written to heap-allocated buffers. This condition creates a scenario where attackers can craft malicious swf files that trigger the overflow when processed by swfrender, potentially allowing for memory corruption that could be exploited to execute arbitrary code. The vulnerability manifests as a classic heap-based buffer overflow, where the function does not properly validate input parameters before performing memory operations, making it susceptible to exploitation through crafted input files.
The operational impact of this vulnerability extends beyond simple memory corruption, as it creates potential attack vectors for remote code execution and system compromise. Systems that rely on swfrender for processing flash content, particularly those in enterprise environments or applications handling user-uploaded swf files, face significant risk. Attackers could leverage this vulnerability to execute malicious code with the privileges of the swfrender process, potentially leading to complete system compromise. The vulnerability's exploitation requires the target system to process a malicious swf file through swfrender, making it particularly concerning for applications that automatically process or render flash content without proper input validation. This scenario aligns with attack patterns documented in the attack technique matrix under software exploitation categories, specifically targeting memory corruption vulnerabilities.
Mitigation strategies for CVE-2023-29950 should prioritize immediate patching of swfrender to version 0.9.3 or later, which contains the necessary fixes for the buffer overflow condition. Organizations should implement strict input validation procedures for all swf files processed by swfrender, including file format validation and size limitation checks to prevent exploitation attempts. Network segmentation and access controls should be implemented to limit exposure of systems running swfrender to untrusted input sources. Additionally, regular security assessments should be conducted to identify similar vulnerabilities in other components of the software stack. The vulnerability aligns with CWE-121 heap-based buffer overflow, and its exploitation techniques correspond to MITRE ATT&CK technique T1059.007 for command and scripting interpreter execution. System administrators should also consider implementing sandboxing mechanisms and privilege separation to limit potential damage from successful exploitation attempts.