Rust advisories / dync
Unsound MediumRUSTSEC-2020-0050 · dync
RUSTSEC-2020-0050: VecCopy allows misaligned access to elements
Short answerdync has an API that can cause undefined behaviour from safe code: VecCopy allows misaligned access to elements. Fixed in 0.5.0.
| Crate | dync |
|---|---|
| Type | Unsound |
| Affected versions | Before 0.5.0. |
| Fixed in | 0.5.0 |
| Severity | Medium, CVSS 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
| Published | 2020-09-27 |
| Last changed | 2023-11-08 |
| Also known as | CVE-2020-35903, GHSA-qxjq-v4wf-ppvh |
What to do
- See which version you have:
cargo tree -i dync(it also shows which of your dependencies pulls it in). - Update within your version requirement:
cargo update -p dync. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for exampledync = "0.5.0") or update the dependency that pulls it in. - Check again with
cargo audit, or paste your Cargo.lock into our Cargo.toml checker.
Details from the advisory
VecCopy::data is created as a Vec of u8 but can be used to store and retrieve elements of different types leading to misaligned access.
The issue was resolved in v0.5.0 by replacing data being stored by Vec<u8> with a custom managed pointer. Elements are now stored and retrieved using types with proper alignment corresponding to original types.
References
- Package: crates.io/crates/dync
- Advisory: rustsec.org/advisories/RUSTSEC-2020-0050.html
- Report: github.com/elrnv/dync/issues/4
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
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