RUSTSEC-2024-0003: Resource exhaustion vulnerability in h2 may lead to Denial of Service (DoS)

What to do

1. See which version you have: cargo tree -i h2 (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p h2. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example h2 = "0.4.2") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

An attacker with an HTTP/2 connection to an affected endpoint can send a steady stream of invalid frames to force the generation of reset frames on the victim endpoint. By closing their recv window, the attacker could then force these resets to be queued in an unbounded fashion, resulting in Out Of Memory (OOM) and high CPU usage.

This fix is corrected in hyperium/h2#737, which limits the total number of internal error resets emitted by default before the connection is closed.

References

• Package: crates.io/crates/h2
• Advisory: rustsec.org/advisories/RUSTSEC-2024-0003.html
• Advisory: github.com/Netflix/security-bulletins/blob/master/advisories/third-party/2019-002.md

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.

Other advisories for h2

• VulnerabilityRUSTSEC-2023-0034 · 2023-04-14Resource exhaustion vulnerability in h2 may lead to Denial of Service (DoS)
• VulnerabilityRUSTSEC-2024-0332 · 2024-04-03Degradation of service in h2 servers with CONTINUATION Flood
• VulnerabilityRUSTSEC-2026-0258 · 2026-08-17h2 unbounded empty DATA frames

Full security history of h2