RUSTSEC-2026-0258: h2 unbounded empty DATA frames

> h2 unbounded empty DATA frames

| Details | |
| ------------------- | ---------------------------------------------- |
| Package | `h2` |
| Version | `0.3.27` |
| URL | [https://github.com/hyperium/hyper/security/advisories/GHSA-q83h-524g-xf6h](https://github.com/hyperium/hyper/security/advisories/GHSA-q83h-524g-xf6h) |
| Date | 2026-08-17 |
| Patched versions | `>=0.4.16` |

The h2 crate, used internally by hyper, had a flaw that would accept and queue empty DATA frames without limit.
If streams were not actively drained, this could lead to unbounded memory usage, or a panic if the length overflows.

Low severity.

Patched in v0.4.16.

See [advisory page](https://rustsec.org/advisories/RUSTSEC-2026-0258.html) for additional details.

Locate where the h2 crate at version 0.3.27 is declared and review the linked hyper security advisory and RustSec entry. Update the dependency to patched version 0.4.16 or later, then run the project's existing tests to confirm the sync server still works.

Written by the indexing model from the issue text.