`WaveFormat::parse` reads past the end of a `&WAVEFORMATEX`

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

`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`.

Source published

8 Sep 2026 12:00:00 UTC

Source modified

7 Oct 2026 14:45:03 UTC

Observed here

24 Oct 2026 13:19:54 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.