CVE-2026-112009 in smpeg
Summary
by MITRE • 10/18/2026
smpeg through 2.0.0 contains a heap out-of-bounds read vulnerability in MPEGsystem::FillBuffer() that allows attackers to read past the 16384-byte buffer by supplying a crafted system header stream table. Attackers can provide an MPEG file whose stream table bytes all set the high bit, which crashes applications opening it through SMPEG_new, SMPEG_new_rwops, or SMPEG_new_data.
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Analysis
by VulDB Data Team • 10/18/2026
The vulnerability identified in smpeg versions up to 2.0.0 represents a critical heap-based out-of-bounds read flaw located within the MPEGsystem::FillBuffer function. This specific implementation error arises when the library processes malformed MPEG system streams, particularly those containing crafted headers designed to exploit memory management logic errors during buffer filling operations. The core technical issue stems from an insufficient validation of stream table parameters before they are used to calculate memory access boundaries. When a malicious actor supplies an MPEG file where the bytes in the stream table have their high bits set, it triggers a condition that causes the application to read data beyond the allocated 16384-byte buffer limit. This behavior is not merely a theoretical edge case but a direct consequence of how the parser interprets specific bit patterns as valid indicators for memory allocation or offset calculation without verifying if those offsets remain within the bounds of the pre-allocated heap segment.
From an operational perspective, this vulnerability poses significant risks to any application that integrates smpeg for audio and video playback functionality. The primary impact is observed when users attempt to open specially crafted MPEG files using functions such as SMPEG_new, SMPEG_new_rwops, or SMPEG_new_data. Upon processing these malicious inputs, the out-of-bounds read can lead to immediate application crashes due to segmentation faults or memory access violations. Beyond simple denial of service, heap-based buffer over-reads are particularly dangerous because they allow attackers to leak sensitive information from adjacent memory regions. Depending on the context in which smpeg is embedded, this could result in the exposure of cryptographic keys, user credentials, or other proprietary data residing in nearby heap allocations. The ability to read arbitrary memory contents effectively transforms a simple parsing bug into a potential remote code execution vector if combined with subsequent exploitation techniques that manipulate control flow based on leaked information.
This vulnerability aligns closely with Common Weakness Enumeration category CWE-125, which describes out-of-bounds read errors where software reads past the end of a buffer or array. The specific mechanism here involves heap memory rather than stack memory, highlighting the importance of rigorous bounds checking in dynamic memory allocation scenarios common in multimedia processing libraries. In terms of tactical classification under MITRE ATT&CK, this behavior corresponds to techniques associated with T1083 File and Directory Discovery if used for reconnaissance or more critically T1204 User Execution if leveraged through social engineering tactics where victims are tricked into opening malicious media files. The exploitation chain typically relies on the victim's trust in the source of the multimedia content, making it a prime candidate for targeted attacks against environments that process untrusted user-uploaded media assets without proper sanitization or sandboxing.
Mitigation strategies must focus on both immediate patching and long-term architectural improvements. Developers should immediately upgrade to patched versions of smpeg where this boundary check has been corrected in the MPEGsystem::FillBuffer routine. For organizations unable to update libraries instantly, implementing strict input validation at the ingestion layer is essential. This includes validating stream headers against known valid ranges before passing them to the decoding engine and enforcing size limits on all buffer operations regardless of header claims. Additionally, deploying runtime protection mechanisms such as Address Sanitizer during testing phases can help identify similar latent issues in multimedia processing codebases. Security teams should also consider implementing sandboxing for any service that processes external media files, ensuring that even if an exploit is successful, its impact is contained within a restricted environment with limited access to sensitive system resources and memory spaces.