How severe is GHSA-q6cp-qfwq-4gcv?

GHSA-q6cp-qfwq-4gcv has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-q6cp-qfwq-4gcv?

GHSA-q6cp-qfwq-4gcv affects the following packages: h2 (crates.io), h2 (crates.io). Ecosystems affected: crates.io.

How do I fix GHSA-q6cp-qfwq-4gcv?

Update h2 to 0.3.26 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-q6cp-qfwq-4gcv is resolved across your whole dependency graph.

How do I detect GHSA-q6cp-qfwq-4gcv in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for h2. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-q6cp-qfwq-4gcv if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-q6cp-qfwq-4gcv?

O3 pinpoints whether GHSA-q6cp-qfwq-4gcv is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-q6cp-qfwq-4gcv actively exploited in the wild?

No public exploit code has been indexed for GHSA-q6cp-qfwq-4gcv yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-q6cp-qfwq-4gcv published, and has it been updated?

GHSA-q6cp-qfwq-4gcv was published on April 5, 2024 and was last updated on February 4, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀 crates.io

GHSA-q6cp-qfwq-4gcv

MEDIUM

h2 servers vulnerable to degradation of service with CONTINUATION Flood

Also known asRUSTSEC-2024-0332

Published

Apr 5, 2024

Updated

Feb 4, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Blast Radius

2 pkgs affected

🦀h2🦀h2

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

An attacker can send a flood of CONTINUATION frames, causing h2 to process them indefinitely. This results in an increase in CPU usage.

Tokio task budget helps prevent this from a complete denial-of-service, as the server can still respond to legitimate requests, albeit with increased latency.

More details at https://seanmonstar.com/blog/hyper-http2-continuation-flood/.

Patches available for 0.4.x and 0.3.x versions.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`h2`	all versions	0.3.26
🦀crates.io	`h2`	≥ 0.4.0&&< 0.4.4	0.4.4

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for h2. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update h2 to 0.3.26 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-q6cp-qfwq-4gcv is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-q6cp-qfwq-4gcv is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-q6cp-qfwq-4gcv. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

An attacker can send a flood of CONTINUATION frames, causing `h2` to process them indefinitely. This results in an increase in CPU usage. Tokio task budget helps prevent this from a complete denial-of-service, as the server can still respond to legitimate requests, albeit with increased latency. More details at https://seanmonstar.com/blog/hyper-http2-continuation-flood/. Patches available for 0.4.x and 0.3.x versions.

O3 Security · Impact-Aware SCA

Is GHSA-q6cp-qfwq-4gcv in your dependencies?

O3 detects GHSA-q6cp-qfwq-4gcv across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works