CVE-2023-45678

What it actually does

Out-of-bounds write in start_decoder due to m->submaps reaching 16 while submap_floor and submap_residue arrays are sized for only 15 elements, enabling memory corruption.

Why it matters to the business

Applications that decode Ogg Vorbis audio can be compromised when a malicious file is processed, potentially allowing attackers to run arbitrary code and disrupt operations or steal data.

How an attack unfolds

An attacker crafts a specially formatted Ogg Vorbis file that sets submap count to the maximum of 16. When the vulnerable library processes the file in start_decoder, the oversized index writes beyond the declared arrays, corrupting memory and allowing code execution in the context of the calling application.

How to fix it

Update the stb_vorbis implementation to ensure submap_floor and submap_residue arrays are sized to accommodate the full maximum of 16 submaps, or replace the library with a patched release once available.

How to confirm the fix worked

Recompile or scan source for array declarations matching the submaps limit, test with a crafted file that exercises maximum submap count, and confirm no writes occur beyond array bounds.

Typical attack path

1. Attacker generates a malicious Ogg Vorbis file with submap count set to 16
2. Victim application loads and decodes the file using the affected library
3. start_decoder performs out-of-bounds write into submap arrays
4. Memory corruption is leveraged for arbitrary code execution

How to detect it

Review application logs for unexpected crashes or errors during Ogg Vorbis decoding, and inspect file-processing code paths for use of the vulnerable start_decoder routine.

What your security team should do

• Identify all products and dependencies that embed stb_vorbis
• Prioritize patching or replacing the library in any media-processing components
• Apply input sanitization or sandboxing around audio decoding until fixed
• Monitor upstream stb_vorbis repository for an official fix