CVE-2022-31394 – This vulnerability in Hyperium Hyper HTTP libra... (How to Fix)

📋 TL;DR

This vulnerability in Hyperium Hyper HTTP libraries allows attackers to perform HTTP/2 attacks by exploiting the inability to customize max_header_list_size limits. It affects applications using Hyper versions before 0.14.19 that enable HTTP/2 functionality.

💻 Affected Systems

Products:

Hyperium Hyper

Versions: All versions before 0.14.19

Operating Systems: All platforms running Rust applications with Hyper

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems with HTTP/2 enabled; HTTP/1.x is not vulnerable. Applications must be using the affected h2 dependency through Hyper.

📦 What is this software?

Hyper by Hyper

View all CVEs affecting Hyper →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Resource exhaustion leading to denial of service, potential for amplification attacks against downstream systems, and disruption of HTTP/2 services.

🟠

Likely Case

HTTP/2 service disruption through header size manipulation, causing connection failures or degraded performance for affected endpoints.

🟢

If Mitigated

Limited impact with proper network segmentation and request filtering; attackers can still target vulnerable endpoints but with reduced effectiveness.

🌐 Internet-Facing: HIGH - HTTP/2 services exposed to the internet are directly vulnerable to unauthenticated attacks.

🏢 Internal Only: MEDIUM - Internal services using HTTP/2 remain vulnerable but have reduced attack surface compared to internet-facing systems.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

HTTP/2 header size manipulation is a well-known attack vector; exploitation requires sending specially crafted HTTP/2 requests.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 0.14.19 and later

Vendor Advisory: https://github.com/hyperium/hyper/security/advisories/GHSA-5h46-h7hh-c6x9

Restart Required: Yes

Instructions:

1. Update Cargo.toml to require hyper >=0.14.19
2. Run 'cargo update hyper'
3. Rebuild and redeploy application
4. Restart affected services

🔧 Temporary Workarounds

Disable HTTP/2

all

Configure Hyper to use only HTTP/1.x protocol

Set appropriate configuration in your Hyper server initialization to disable HTTP/2 support

Network-level filtering

all

Implement WAF or proxy rules to limit HTTP/2 header sizes

🧯 If You Can't Patch

Implement reverse proxy with HTTP/2 header size limits
Deploy network segmentation to isolate vulnerable services

🔍 How to Verify

Check if Vulnerable:

Check Cargo.lock or run 'cargo tree | grep hyper' to see if hyper version is <0.14.19

Check Version:

cargo tree | grep -E '^hyper\s' | head -1

Verify Fix Applied:

Verify hyper version is >=0.14.19 in Cargo.lock and test HTTP/2 functionality

📡 Detection & Monitoring

Log Indicators:

HTTP/2 connection resets
Unusually large header sizes in logs
Protocol errors in HTTP/2 sessions

Network Indicators:

Excessive HTTP/2 HEADERS frames
Abnormal header list sizes in HTTP/2 traffic
Connection termination after HEADERS frames

SIEM Query:

http.protocol="HTTP/2" AND (http.header_size>threshold OR error.message CONTAINS "header_size")

📊 Metadata

CVE ID: CVE-2022-31394

CVSS v3 Score: 7.5 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE: CWE-770

Published: February 21, 2023

Last Updated: March 17, 2025

🔗 References

https://github.com/hyperium/hyper/compare/v0.14.18...v0.14.19 Patch
https://github.com/hyperium/hyper/issues/2826 Exploit,Issue Tracking,Patch,Vendor Advisory
https://github.com/hyperium/hyper/pull/2828 Issue Tracking,Patch
https://github.com/hyperium/hyper/compare/v0.14.18...v0.14.19 Patch
https://github.com/hyperium/hyper/issues/2826 Exploit,Issue Tracking,Patch,Vendor Advisory
https://github.com/hyperium/hyper/pull/2828 Issue Tracking,Patch

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🔗 Related Vulnerabilities

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