{"id":"CVE-2026-111750","kind":"vulnerability","aliases":["CVE-2026-111750","GHSA-pqxq-w44r-73xw"],"related":[],"title":"AIOHTTP: Pure-Python parser request smuggling","description":"AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the pure Python parser accepts ambiguous HTTP request framing. An unauthenticated attacker can consequently smuggle requests when an application uses AIOHTTP_NO_EXTENSIONS or otherwise runs without a standard wheel and an intermediary interprets the framing differently. This issue is fixed in version 3.14.4.","summary":"aiohttp's pure-Python HTTP parser can be tricked into request smuggling (CWE-444), where a front-end proxy and the aiohttp backend disagree on where one request ends. An attacker who can send crafted requests can slip hidden requests past front-end controls.","severity":"medium","cvss":6.3,"epss":0.0030400000978261232,"exploited":false,"exploited_at":null,"products":[{"name":"aiohttp","fixed":["3.14.4"],"affected":"<= 3.14.3","ecosystem":"pypi"}],"ecosystems":["pypi"],"tags":["aiohttp","cwe-444","package","python","reverse-proxy","self-hosted"],"not_affected_if":["default-c-parser","no-pure-python-fallback"],"how_to_check":"Check whether AIOHTTP_NO_EXTENSIONS is set in the environment, or whether aiohttp was installed without a compiled C-extension wheel (e.g. pip show aiohttp and confirm the C parser is in use).","fix":"Upgrade aiohttp to 3.14.4 or later.\nOr switch to the default C parser by installing a standard wheel and unsetting AIOHTTP_NO_EXTENSIONS.","status":"open","published_at":"2026-10-19T17:17:04+00:00","first_seen_at":"2026-10-23T19:11:32+00:00","triaged_at":"2026-10-23T20:13:28+00:00","updated_at":"2026-10-23T21:57:18+00:00","category":"package","confidence":0.8,"triage":{"at":"2026-10-23T20:13:28Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade aiohttp to 3.14.4 or later.\nOr switch to the default C parser by installing a standard wheel and unsetting AIOHTTP_NO_EXTENSIONS.","summary":"aiohttp's pure-Python HTTP parser can be tricked into request smuggling (CWE-444), where a front-end proxy and the aiohttp backend disagree on where one request ends. An attacker who can send crafted requests can slip hidden requests past front-end controls.","category":"package","who_cares":["python","aiohttp","self-hosted","reverse-proxy"],"confidence":0.8,"analyst_note":"","how_to_check":"Check whether AIOHTTP_NO_EXTENSIONS is set in the environment, or whether aiohttp was installed without a compiled C-extension wheel (e.g. pip show aiohttp and confirm the C parser is in use).\nunknown\nunknown","needs_analyst":false,"not_affected_if":["default-c-parser","no-pure-python-fallback"],"severity_if_unknown":"medium"},"cost_usd":0.000391,"input_tokens":2069,"output_tokens":369,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-111750':10A,18A '-2026':9A,17A '-444':22B,45B '3.14.4':91C,135C '73xw':15A 'accept':96C 'aiohttp':1A,19A,20B,31B,54B,78C,112C 'ambigu':97C 'applic':110C 'asynchron':81C 'asyncio':86C 'attack':63B,103C 'backend':55B 'client/server':83C 'consequ':105C 'control':77B 'craft':67B 'cve':8A,16A 'cwe':21B,44B 'differ':128C 'disagre':56B 'end':50B,61B,76B 'extens':114C 'fix':132C 'frame':100C,127C 'framework':84C 'front':49B,75B 'front-end':48B,74B 'ghsa':12A 'ghsa-pqxq-w44r-73xw':11A 'hidden':71B 'host':30B 'http':36B,82C,98C 'intermediari':124C 'interpret':125C 'issu':130C 'one':59B 'otherwis':116C 'packag':23B 'parser':5A,37B,95C 'past':73B 'pqxq':13A 'prior':89C 'proxi':27B,51B 'pure':3A,34B,93C 'pure-python':2A,33B 'python':4A,24B,35B,88C,94C 'request':6A,42B,60B,68B,72B,99C,107C 'revers':26B 'reverse-proxi':25B 'run':117C 'self':29B 'self-host':28B 'send':66B 'slip':70B 'smuggl':7A,43B,106C 'standard':120C 'trick':40B 'unauthent':102C 'use':111C 'version':134C 'w44r':14A 'wheel':121C 'without':118C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-19T17:17:04+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:L/SA:L/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","cvss_by":"security-advisories@github.com","poc_count":0,"sources":[{"source":"ghsa","external_id":"GHSA-pqxq-w44r-73xw","url":"https://github.com/advisories/GHSA-pqxq-w44r-73xw","severity":"medium","published_at":"2026-10-20T19:52:21+00:00","modified_at":"2026-10-20T19:52:22+00:00","first_seen_at":"2026-10-23T19:11:32+00:00","fetched_at":"2026-10-23T19:11:32+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-111750","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-111750","severity":null,"published_at":"2026-10-19T17:17:04+00:00","modified_at":"2026-10-19T20:55:02+00:00","first_seen_at":"2026-10-23T21:57:18+00:00","fetched_at":"2026-10-23T22:28:57+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}