Multiple vulnerabilities resulting in out-of-bounds writes

* The heap initialization methods were missing a minimum size check for the given heap size argument. This could lead to **out-of-bound writes** when a heap was initialized with a size smaller than `3 * size_of::<usize>` because of metadata write operations. * When calling `Heap::extend` with a size smaller than two `usize`s (e.g., 16 on `x86_64`), the size was erroneously rounded up to the minimum size, which could result in an **out-of-bounds write**. * Calling `Heap::extend` on an empty heap tried to construct a heap starting at address 0, which is also an **out-of-bounds write**. * One specific way to trigger this accidentally is to call `Heap::new` (or a similar constructor) with a heap size that is smaller than two `usize`s. This was treated as an empty heap as well. * Calling `Heap::extend` on a heap whose size is not a multiple of the size of two `usize`s resulted in unaligned writes. It also left the heap in an unexpected state, which might lead to subsequent issues. We did not find a way to exploit this undefined behavior yet (apart from DoS on platforms that fault on unaligned writes).

Source published

7 Sep 2022 12:00:00 UTC

Source modified

12 Oct 2026 18:00:02 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.

CVSS_V3 · CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H