RUSTSEC-2026-0258: h2 unbounded empty DATA frames

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
72/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
rust
Domain
backend, security

Research direction

Start by locating the Cargo manifest and lockfile entries for the h2 crate and check the resolved version. Update the dependency to a patched version at or above 0.4.16, then run the repository's existing Rust checks. Done means the project resolves the patched h2 release without introducing dependency conflicts.

Written by the indexing model from the issue text.

Description

h2 unbounded empty DATA frames

Details
Package h2
Version 0.4.13
URL 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 for additional details.

Dominant language
Rust
Stars
2.7k
Forks
162
Avg merge
1d 14h
Merged PRs (30d)
7

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

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