CVE-2023-45677 in stb_vorbis
Summary
by MITRE • 10/25/2023
stb_vorbis is a single file MIT licensed library for processing ogg vorbis files. A crafted file may trigger out of bounds write in `f->vendor[len] = (char)'\0';`. The root cause is that if `len` read in `start_decoder` is a negative number and `setup_malloc` successfully allocates memory in that case, but memory write is done with a negative index `len`. Similarly if len is INT_MAX the integer overflow len+1 happens in `f->vendor = (char*)setup_malloc(f, sizeof(char) * (len+1));` and `f->comment_list[i] = (char*)setup_malloc(f, sizeof(char) * (len+1));`. This issue may lead to code execution.
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Analysis
by VulDB Data Team • 04/21/2025
The vulnerability identified as CVE-2023-45677 resides within the stb_vorbis library, a widely-used single-file implementation for processing ogg vorbis audio files under the MIT license. This library serves as a critical component in numerous applications and systems that handle audio processing, making this vulnerability particularly concerning from a security perspective. The flaw manifests as an out-of-bounds write condition that occurs during the parsing of crafted vorbis files, specifically within the vendor string handling mechanism of the decoding process.
The technical root cause of this vulnerability stems from improper input validation and integer overflow handling within the `start_decoder` function. When the length parameter `len` is read from a malformed file, several dangerous scenarios can occur. First, if `len` is a negative number, the memory allocation logic in `setup_malloc` may still succeed, but subsequent memory writes to `f->vendor[len]` execute with a negative index, creating undefined behavior. Additionally, when `len` equals INT_MAX, integer overflow occurs during the arithmetic operation `len+1` in the memory allocation statements, leading to allocation of insufficient memory while the code attempts to write beyond allocated boundaries. This dual vulnerability scenario creates multiple pathways for exploitation.
The operational impact of CVE-2023-45677 extends beyond simple memory corruption, potentially enabling remote code execution in vulnerable systems. Attackers can craft malicious ogg vorbis files that, when processed by applications using the affected stb_vorbis library, trigger the out-of-bounds write conditions. The vulnerability's severity is amplified by the library's widespread adoption across various software platforms, including media players, game engines, and multimedia applications. This makes the attack surface extensive and potentially affects numerous end-user systems and server environments that process user-uploaded audio content.
Security mitigations for this vulnerability should focus on input validation and bounds checking within the stb_vorbis library implementation. The most effective approach involves adding explicit checks to ensure that `len` values remain within valid ranges before memory allocation and subsequent writes. This aligns with CWE-129, which addresses improper validation of array indices, and CWE-190, which covers integer overflow conditions. Additionally, implementing proper integer overflow detection and bounds checking in memory allocation functions would prevent the dangerous arithmetic operations that lead to the vulnerability. Organizations should also consider updating to patched versions of the stb_vorbis library, as recommended by the maintainers, and conduct thorough security reviews of applications that utilize this library to identify potential attack vectors and ensure proper input sanitization mechanisms are in place.
The vulnerability demonstrates characteristics consistent with ATT&CK technique T1203, which involves exploitation of software vulnerabilities for privilege escalation or code execution. The combination of integer overflow and out-of-bounds write conditions creates a robust attack surface that could be leveraged by adversaries to gain unauthorized control over affected systems. Given the library's integration into numerous software ecosystems, this vulnerability represents a significant risk that requires immediate attention from both library maintainers and downstream application developers to prevent potential exploitation in real-world scenarios.