RUSTSEC-2026-0332 json
`WaveFormat::parse` reads past the end of a `&WAVEFORMATEX`
published 2mo ago modified last mo.
- cvss
- —
- not scored
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- —
- no score, EPSS covers CVEs only
- public exploits
- 0
- none known
Summary
`WaveFormat::parse` is a safe function that takes a `&WAVEFORMATEX`, which is only valid for reads of `size_of::<WAVEFORMATEX>()` (18) bytes. When the header has `wFormatTag == WAVE_FORMAT_EXTENSIBLE` and `cbSize >= 22`, the function reinterprets the reference as a `WAVEFORMATEXTENSIBLE` and reads 40 bytes. Nothing in the signature guarantees that the header sits at the start of a larger buffer, so safe code can trigger an out-of-bounds read:
```rust use wasapi::WaveFormat; use windows::Win32::Media::Audio::WAVEFORMATEX; use windows::Win32::Media::KernelStreaming::WAVE_FORMAT_EXTENSIBLE;
let header = WAVEFORMATEX { wFormatTag: WAVE_FORMAT_EXTENSIBLE as u16, nChannels: 2, nSamplesPerSec: 48000, nAvgBytesPerSec: 384000, nBlockAlign: 8, wBitsPerSample: 32, cbSize: 22, }; // Reads 22 bytes past the end of `header`. let _ = WaveFormat::parse(&header); ```
A more likely way to hit this is to copy the header out of a format pointer returned by WASAPI (`let fmt = unsafe { *ptr };`) and pass `&fmt`. The copy keeps `cbSize`, but not the 22 bytes that follow it. The bytes read past the end are returned as the channel mask and subformat of the parsed format.
The flaw was corrected in commit `2562db7`, released in 0.25.0. `parse` is now an `unsafe fn` that takes a `*const WAVEFORMATEX`, and the caller must guarantee that the pointer is valid for reads of `size_of::<WAVEFORMATEX>() + cbSize` bytes. `WaveFormat::parse_from_blob_bytes` (available since 0.23.0) is the safe alternative and checks the slice length against `cbSize`.
Patch / fix
Is RUSTSEC-2026-0332 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerAffected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| crates.io | wasapi | >=0.20.0, <0.25.0 |
0.25.0 |
References
Sources
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