CVE-2026-116741 in Speex
Summary
by MITRE • 10/27/2026
Speex (libspeex) through 1.2.1 contains an out-of-bounds write vulnerability in speex_bits_read_whole_bytes() in libspeex/bits.c that mishandles length truncation for non-owned SpeexBits buffers. Attackers can stream crafted Speex data into buffers set up with speex_bits_init_buffer() or speex_bits_set_bit_buffer() to corrupt heap or stack memory and crash applications.
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Analysis
by VulDB Data Team • 10/27/2026
The vulnerability identified in the Speex audio codec library, specifically within versions through 1.2.1, represents a critical security flaw located in the function speex_bits_read_whole_bytes found in libspeex/bits.c. This component is responsible for parsing and processing bitstream data during the decoding of Speex-encoded audio files or streams. The core technical issue stems from an improper handling of length truncation when dealing with non-owned SpeexBits buffers. In normal operation, the library initializes buffer structures using functions such as speex_bits_init_buffer() or speex_bits_set_bit_buffer(), which set up a memory region for reading data without necessarily taking ownership of that memory's lifecycle management. The flaw arises because the read function fails to correctly validate whether the requested number of bytes exceeds the actual available length in these externally managed buffers, leading to an out-of-bounds write condition when crafted input is provided.
From a technical perspective, this vulnerability allows an attacker who can supply maliciously constructed Speex data to trigger a heap or stack buffer overflow. When speex_bits_read_whole_bytes() processes a stream where the specified length does not account for truncation boundaries in non-owned buffers, it writes data beyond the allocated memory limits. This corruption of adjacent memory structures can lead to immediate application crashes due to segmentation faults or access violations. More severely, if the attacker has control over the content being written into these out-of-bounds regions, they may achieve arbitrary code execution by overwriting critical program pointers such as return addresses on the stack or function pointers in heap metadata. This transforms a simple denial of service scenario into a potential remote code execution vector depending on how the vulnerable library is integrated into the host application and whether user-controlled data can be injected into the decoding pipeline.
The operational impact of this vulnerability extends beyond immediate stability issues to significant security risks for any software that relies on libspeex for audio processing, including VoIP applications, conferencing tools, media players, and embedded communication systems. An attacker could exploit this flaw by tricking a victim into opening a specially crafted Speex file or connecting to a malicious streaming server that delivers the payload in real-time. The resulting memory corruption can destabilize the entire application environment, potentially leading to data leakage if sensitive information resides near the corrupted buffers, or complete system compromise if privilege escalation is possible through further exploitation techniques following the initial code execution.
This vulnerability aligns with CWE-787: Out-of-bounds Write, which describes writing data outside of intended boundaries, and can be mapped to MITRE ATT&CK technique T1203: Exploitation for Client Execution if leveraged in a client-side attack scenario where user interaction is required. To mitigate this risk, organizations utilizing libspeex must immediately upgrade to version 1.2.2 or later, which includes patches that enforce strict bounds checking on buffer lengths before performing write operations. Developers integrating the library should also implement input validation at higher levels of their application logic to ensure that only well-formed and size-constrained Speex streams are passed to the decoder. Additionally, enabling compiler-based protections such as stack canaries, Address Space Layout Randomization (ASLR), and Data Execution Prevention (DEP) can help mitigate the impact of successful exploitation attempts by making it more difficult for attackers to reliably execute arbitrary code in memory-corrupted environments.