CVE-2026-95125 in libming
Summary
by MITRE • 10/08/2026
libming through 0.4.8 contains a heap buffer overflow in r_readc() in src/blocks/fromswf.c. A crafted SWF file with a malformed or truncated RECT header can cause a denial of service.
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Analysis
by VulDB Data Team • 10/08/2026
The vulnerability identified in libming versions up to and including 0.4.8 represents a critical memory safety issue located within the r_readc function found in the src/blocks/fromswf.c source file. This library is widely utilized for parsing, manipulating, and rendering SWF (Small Web Format) files, which are commonly associated with Adobe Flash content. The core of this vulnerability lies in how the parser handles input data structures that define geometric boundaries or rectangular regions within a SWF stream. Specifically, when processing these records, the function fails to adequately validate the length or bounds of the incoming RECT header before attempting to read and process its contents. This lack of rigorous boundary checking creates an environment where malformed or truncated inputs can trigger unsafe memory operations.
From a technical perspective, this flaw manifests as a heap buffer overflow. When a crafted SWF file containing a malformed RECT header is processed, the r_readc function attempts to access memory locations beyond the allocated bounds of the internal buffers used for parsing. This occurs because the parser does not correctly calculate or verify the size of the data segment it intends to read based on the provided header information. Consequently, the application writes data into adjacent memory regions that are not intended for this purpose. In many cases, such as with truncated headers, the function may attempt to read more bytes than are actually available in the input stream, leading to out-of-bounds reads or writes depending on the specific implementation details of the buffer management logic within libming.
The operational impact of this vulnerability is primarily a denial of service condition for applications that rely on libming to process SWF files. An attacker can exploit this flaw by distributing maliciously crafted SWF files designed with specifically malformed RECT headers. When an unsuspecting user or server processes such a file, the resulting heap buffer overflow corrupts memory structures within the application's address space. This corruption typically leads to immediate program crashes, causing service interruptions for end-users or backend systems processing multimedia content. While modern operating system protections like Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP) may mitigate some aspects of exploitation by making reliable code execution difficult, they do not prevent the initial crash that results in a denial of service.
This vulnerability aligns with CWE-120, which describes buffer copy without checking size limits, specifically highlighting the failure to validate input data before performing memory operations. Furthermore, from an offensive security perspective, this flaw can be categorized under ATT&CK technique T1496, which involves Resource Hijacking through denial of service attacks. The ability to crash a parser via malformed input is a common vector for disrupting availability in multimedia processing pipelines. To mitigate this risk, developers and system administrators should immediately update libming to versions newer than 0.4.8 where the r_readc function has been patched with proper bounds checking mechanisms. Additionally, implementing strict input validation at the application layer before passing SWF data to the library can provide an additional defense-in-depth measure against such malformed inputs.