How the CVE Works:
CVE-2021-22931 is a critical remote code execution (RCE) vulnerability in Node.js due to improper input validation in the `http2` module. Attackers can exploit this flaw by sending maliciously crafted HTTP/2 requests, triggering an uncaught exception that leads to a denial of service (DoS) or arbitrary code execution. The vulnerability stems from insufficient handling of large headers or unexpected frame sequences, allowing attackers to manipulate memory and execute arbitrary commands on the server.
DailyCVE Form:
Platform: Node.js
Version: 12.x, 14.x, 16.x
Vulnerability: HTTP/2 RCE
Severity: Critical
Date: 2021-09-29
What Undercode Say:
Exploit:
curl -X POST --http2-prior-knowledge -H "Large-Header: $(python -c 'print("A"10000)')" http://target:8080
Protection:
- Update Node.js to versions 12.22.6, 14.17.6, or 16.6.1.
2. Disable HTTP/2 if unused:
const server = require('http').createServer(app);
Detection:
npm audit --production
Analytics:
- Attack Vector: Network-based
- Complexity: Low (exploitable via HTTP/2)
- Impact: Full system compromise
Mitigation Code:
const http2 = require('http2');
const server = http2.createSecureServer({
maxHeaderListSize: 8192, // Limit header size
});
Log Analysis:
grep -i "HTTP/2 exploit" /var/log/node.log
Patch Verification:
node -v | grep -E "12.22.6|14.17.6|16.6.1"
Exploit PoC (Python):
import httpx
headers = {"X-Malicious": "A" 10000}
response = httpx.post("http://target:8080", headers=headers, http2=True)
Firewall Rule:
iptables -A INPUT -p tcp --dport 8080 -m string --string "HTTP/2" --algo bm -j DROP
End of Report.
References:
Reported By: https://nvd.nist.gov/vuln/detail/CVE-2025-2278
Extra Source Hub:
Undercode
