RUSTSEC-2026-0235: Insufficient archive validation can cause out-of-bounds reads in archives containing Rc/Arc

> Insufficient archive validation can cause out-of-bounds reads in archives containing Rc/Arc

| Details | |
| ------------------- | ---------------------------------------------- |
| Package | `rkyv` |
| Version | `0.7.46` |
| URL | [https://github.com/rkyv/rkyv/issues/670](https://github.com/rkyv/rkyv/issues/670) |
| Date | 2026-05-13 |
| Patched versions | `>=0.8.17` |
| Unaffected versions | `<0.7.0-pre.2` |

Shared pointer validation keyed already-validated pointees by their address and
type, but did not include pointer metadata. For unsized pointees, an archive
could therefore contain multiple `Rc`, `Arc`, or weak pointers that shared a
data address but used different metadata, such as different slice lengths.

Once the first pointer had been validated, later pointers to the same address
skipped pointee validation. The safe checked `rkyv::access` API could
consequently return a slice with a forged length, allowing safe indexing to
read out of bounds. The same validation bypass was reachable through checked
deserialization with `rkyv::from_bytes`.

Version 0.8.17 includes pointer metadata in shared pointer validation and
rejects conflicting metadata. The 0.7 series is also affected but is no
longer supported by upstream. Users who process untrusted archives should upgrade
to 0.8.17 or later.

See [advisory page](https://rustsec.org/advisories/RUSTSEC-2026-0235.html) for additional details.

The issue identifies rkyv 0.7.46 as affected and recommends upgrading to 0.8.17 or later. Check the repository's Rust dependency configuration for rkyv, update the dependency and any resulting lockfile changes, then verify the workspace still builds and its existing checks pass.

Written by the indexing model from the issue text.