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How the CVE Works
CVE-2021-22931 is a critical remote code execution vulnerability in Node.js due to improper input validation in the `http2` module. An attacker can exploit this flaw by sending a specially crafted HTTP/2 request, triggering an uncaught exception that crashes the server or allows arbitrary code execution. The issue stems from insufficient handling of large header fields, leading to a buffer overflow. Attackers can leverage this to bypass security restrictions, execute malicious payloads, or cause denial-of-service conditions.
DailyCVE Form
Platform: Node.js
Version: 12.x – 16.x
Vulnerability: HTTP/2 RCE
Severity: Critical
Date: 2021-09-01
Prediction: Patch by 2021-09-15
What Undercode Say
Check Node.js version
node -v
Exploit PoC (simulated crash)
curl --http2-prior-knowledge -H "Large-Header: $(python -c 'print("A"10000)')" http://target
Mitigation command
npm update -g node@latest
How Exploit
- Craft malicious HTTP/2 requests with oversized headers.
- Trigger buffer overflow to crash the server or execute code.
- Bypass sandbox restrictions via heap corruption.
Protection from this CVE
- Upgrade to Node.js 12.22.6, 14.18.0, or 16.9.0.
- Disable HTTP/2 if unused.
- Implement WAF rules to filter oversized headers.
Impact
- Remote code execution.
- Denial-of-service (DoS).
- Compromise of server integrity.
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
