`Seekable::decompress` sets a `Vec` length beyond its capacity for offsets past the end

`ZSTD_seekable_decompress` shortens the requested length to the end of the data without checking that the offset is before it. For an offset past the end, it returns a wrapped-around length without writing anything, and `Seekable::decompress` passed that length to `Vec::set_len`. With the `seekable` feature, whoever supplies the archive, or chooses the offset, can leave the caller's `Vec<u8>` with a length far beyond its capacity. Reading it then discloses neighbouring heap memory, and appending to it corrupts memory. Offsets near `u64::MAX` can also hang the call. The flaw was corrected by clamping requests to the end of the data, and by checking every count reported by the C library against the buffer capacity.

Source published

16 Oct 2026 12:00:00 UTC

Source modified

26 Oct 2026 14:00:05 UTC

Observed here

26 Oct 2026 14:35:44 UTC

Source terms

OSV · upstream source license applies

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