{"id":"CVE-2026-119131","kind":"vulnerability","aliases":["CVE-2026-119131"],"related":[],"title":"Wasmtime: long request URLs let a guest crash the host","description":"Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a denial of service vulnerability in wasmtime-wasi-http that lets guests crash the host by sending long request URLs. Guests can use set-path-with-query with a '?' after byte 65535, overflowing a u16 index in the http crate and triggering a host panic.","summary":"Wasmtime's wasmtime-wasi-http component mishandles request URLs with a '?' after byte 65535 because of a u16 index overflow in the http crate. A guest module can send such a URL and crash the host process with a panic, causing denial of service.","severity":"medium","cvss":6.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["plugin-hosts","runtime","wasmtime","webassembly"],"not_affected_if":["trusted-guests-only","version-outside-range","wasi-http-unused"],"how_to_check":"- Check the wasmtime version in your build, for example with `cargo tree -i wasmtime` or the lockfile.\n- Confirm whether wasmtime-wasi-http is in use, since the flaw is in that crate.","fix":"- Wasmtime `48.0.6` for the 48 line.\n- Wasmtime `49.0.3` for the 49 line.","status":"open","published_at":"2026-10-29T16:18:06+00:00","first_seen_at":"2026-10-29T16:25:58+00:00","triaged_at":"2026-10-29T16:30:09+00:00","updated_at":"2026-10-29T16:30:09+00:00","category":"runtime","confidence":0.7,"triage":{"at":"2026-10-29T16:30:09Z","model":"claude-haiku-5-5","output":{"fix":"- Wasmtime `48.0.6` for the 48 line.\n- Wasmtime `49.0.3` for the 49 line.","reach":"unknown","title":"Wasmtime: long request URLs let a guest crash the host","impact":"low","summary":"Wasmtime's wasmtime-wasi-http component mishandles request URLs with a '?' after byte 65535 because of a u16 index overflow in the http crate. A guest module can send such a URL and crash the host process with a panic, causing denial of service.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["wasmtime","webassembly","plugin-hosts"],"confidence":0.7,"fix_status":"available","needs_auth":"unknown","worst_case":"Host process panics and crashes, causing denial of service","analyst_note":"","how_to_check":"- Check the wasmtime version in your build, for example with `cargo tree -i wasmtime` or the lockfile.\n- Confirm whether wasmtime-wasi-http is in use, since the flaw is in that crate.","plain_action":"","needs_analyst":false,"not_affected_if":["wasi-http-unused","trusted-guests-only","version-outside-range"],"who_is_affected":"Only hosts running Wasmtime 46.0.0 before 48.0.6 or 49.0.0 before 49.0.3 with wasmtime-wasi-http, which lets untrusted guest code send HTTP requests. Teams that only run trusted guests or do not use the wasi-http feature can deprioritise it.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000701,"input_tokens":4165,"output_tokens":569,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-119131':13A,16A '-2026':12A,15A '46.0.0':69C '48.0.6':71C '49.0.0':73C '49.0.3':75C '65535':37B,110C 'byte':36B,109C 'caus':64B 'compon':29B 'contain':76C 'crash':8A,57B,90C 'crate':47B,118C 'cve':11A,14A 'denial':65B,78C 'guest':7A,49B,89C,98C 'host':10A,19B,59B,92C,122C 'http':28B,46B,86C,117C 'index':42B,114C 'let':5A,88C 'long':2A,95C 'mishandl':30B 'modul':50B 'overflow':43B,111C 'panic':63B,123C 'path':103C 'plugin':18B 'plugin-host':17B 'process':60B 'queri':105C 'request':3A,31B,96C 'runtim':20B 'send':52B,94C 'servic':67B,80C 'set':102C 'set-path-with-queri':101C 'trigger':120C 'u16':41B,113C 'url':4A,32B,55B,97C 'use':100C 'vulner':81C 'wasi':27B,85C 'wasmtim':1A,21B,23B,26B,68C,84C 'wasmtime-wasi-http':25B,83C 'webassembl':22B","nicknames":[],"mitigations":[],"who_affected":"Only hosts running Wasmtime 46.0.0 before 48.0.6 or 49.0.0 before 49.0.3 with wasmtime-wasi-http, which lets untrusted guest code send HTTP requests. Teams that only run trusted guests or do not use the wasi-http feature can deprioritise it.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"first_public_at":"2026-10-29T16:18:06+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-119131","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-119131","severity":null,"published_at":"2026-10-29T16:18:06+00:00","modified_at":"2026-10-29T16:18:06+00:00","first_seen_at":"2026-10-29T16:25:58+00:00","fetched_at":"2026-10-29T16:25:58+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"}