{"id":"CVE-2026-119137","kind":"vulnerability","aliases":["CVE-2026-119137"],"related":[],"title":"Wasmtime: recursive type drops let a guest crash the host","description":"Wasmtime 42.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a stack overflow vulnerability that allows guests to crash the host through recursive type drops. Guests can define a long chain of recursive types so that removing the top-level type triggers unbounded recursive drops, exhausting the host stack.","summary":"Wasmtime versions 42.0.0 through 48.0.5 and 49.0.0 through 49.0.2 can be made to overflow the host stack when a guest defines a long chain of recursive types and that top-level type is removed. An attacker running untrusted WebAssembly guest code can crash the host process.","severity":"medium","cvss":6.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["runtime","rust","wasmtime","webassembly"],"not_affected_if":["no-wasmtime","trusted-guests-only"],"how_to_check":"- Run `wasmtime --version` (or check the Wasmtime crate version in `Cargo.lock`) and compare against the affected ranges 42.0.0 to before 48.0.6 and 49.0.0 to before 49.0.3.\n- Check whether your application runs untrusted or user-supplied WebAssembly guests on Wasmtime.","fix":"- Wasmtime `48.0.6` for the 48.x line\n- Wasmtime `49.0.3` for the 49.x line","status":"open","published_at":"2026-10-29T16:18:07+00:00","first_seen_at":"2026-10-29T16:25:58+00:00","triaged_at":"2026-10-29T16:30:08+00:00","updated_at":"2026-10-29T16:30:08+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-10-29T16:30:08Z","model":"claude-haiku-5-5","output":{"fix":"- Wasmtime `48.0.6` for the 48.x line\n- Wasmtime `49.0.3` for the 49.x line","reach":"local","title":"Wasmtime: recursive type drops let a guest crash the host","impact":"low","summary":"Wasmtime versions 42.0.0 through 48.0.5 and 49.0.0 through 49.0.2 can be made to overflow the host stack when a guest defines a long chain of recursive types and that top-level type is removed. An attacker running untrusted WebAssembly guest code can crash the host process.","audience":"developers","category":"runtime","nicknames":[],"who_cares":["wasmtime","webassembly","rust"],"confidence":0.6,"fix_status":"available","needs_auth":"no","worst_case":"guest crashes the host process via stack exhaustion","analyst_note":"","how_to_check":"- Run `wasmtime --version` (or check the Wasmtime crate version in `Cargo.lock`) and compare against the affected ranges 42.0.0 to before 48.0.6 and 49.0.0 to before 49.0.3.\n- Check whether your application runs untrusted or user-supplied WebAssembly guests on Wasmtime.","plain_action":"","needs_analyst":false,"not_affected_if":["trusted-guests-only","no-wasmtime"],"who_is_affected":"Only systems that load and run untrusted WebAssembly guests with Wasmtime 42.x or 49.x (before the fixed versions) are exposed; a guest can crash the host through recursive type drops. Teams running only trusted modules or not using Wasmtime can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000715,"input_tokens":4158,"output_tokens":598,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-119137':13A,16A '-2026':12A,15A '42.0.0':23B,69C '48.0.5':25B '48.0.6':71C '49.0.0':27B,73C '49.0.2':29B '49.0.3':75C 'allow':82C 'attack':57B 'chain':44B,97C 'code':62B 'contain':76C 'crash':8A,64B,85C 'cve':11A,14A 'defin':41B,94C 'drop':4A,91C,112C 'exhaust':113C 'guest':7A,40B,61B,83C,92C 'host':10A,36B,66B,87C,115C 'let':5A 'level':52B,107C 'long':43B,96C 'made':32B 'overflow':34B,79C 'process':67B 'recurs':2A,46B,89C,99C,111C 'remov':55B,103C 'run':58B 'runtim':17B 'rust':18B 'stack':37B,78C,116C 'top':51B,106C 'top-level':50B,105C 'trigger':109C 'type':3A,47B,53B,90C,100C,108C 'unbound':110C 'untrust':59B 'version':22B 'vulner':80C 'wasmtim':1A,19B,21B,68C 'webassembl':20B,60B","nicknames":[],"mitigations":[],"who_affected":"Only systems that load and run untrusted WebAssembly guests with Wasmtime 42.x or 49.x (before the fixed versions) are exposed; a guest can crash the host through recursive type drops. Teams running only trusted modules or not using Wasmtime can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"first_public_at":"2026-10-29T16:18:07+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-2026-119137","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-119137","severity":null,"published_at":"2026-10-29T16:18:07+00:00","modified_at":"2026-10-29T16:18:07+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"}