{"id":"CVE-2026-119142","kind":"vulnerability","aliases":["CVE-2026-119142"],"related":[],"title":"Wasmtime: dropping a pending async call can panic 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 where dropping the Future returned by TypedFunc::call_async can panic the host. When the guest task has not started, cleanup code searches only one location for work items and unwraps the resulting error, crashing embedders that cancel pending calls.","summary":"Wasmtime versions 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 panic when the Future returned by TypedFunc::call_async is dropped before the guest task starts. An attacker who can make an embedder cancel pending calls crashes the host process, causing denial of service.","severity":"medium","cvss":5.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["embedders","runtime","rust","wasm-plugins","wasmtime"],"not_affected_if":["no-async-typed-calls","versions-outside-range"],"how_to_check":"- Check the Wasmtime version your application links against, for example with `cargo tree -i wasmtime` in a Rust project.\n- Look for embedders that call `TypedFunc::call_async` and may drop or cancel those futures, such as timeouts or client disconnects.","fix":"- Move to `48.0.6` or later on the 48 line.\n- Move to `49.0.3` or later on the 49 line.","status":"open","published_at":"2026-10-29T16:18:07+00:00","first_seen_at":"2026-10-29T16:25:58+00:00","triaged_at":"2026-10-29T16:31:35+00:00","updated_at":"2026-10-29T16:31:35+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-10-29T16:31:35Z","model":"claude-haiku-5-5","output":{"fix":"- Move to `48.0.6` or later on the 48 line.\n- Move to `49.0.3` or later on the 49 line.","reach":"unknown","title":"Wasmtime: dropping a pending async call can panic the host","impact":"low","summary":"Wasmtime versions 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 panic when the Future returned by TypedFunc::call_async is dropped before the guest task starts. An attacker who can make an embedder cancel pending calls crashes the host process, causing denial of service.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["wasmtime","rust","embedders","wasm-plugins"],"confidence":0.6,"fix_status":"available","needs_auth":"unknown","worst_case":"host process crashes when embedder cancels pending calls","analyst_note":"","how_to_check":"- Check the Wasmtime version your application links against, for example with `cargo tree -i wasmtime` in a Rust project.\n- Look for embedders that call `TypedFunc::call_async` and may drop or cancel those futures, such as timeouts or client disconnects.","plain_action":"","needs_analyst":false,"not_affected_if":["no-async-typed-calls","versions-outside-range"],"who_is_affected":"Applications that embed Wasmtime and call async typed functions, where cancelling a pending call (through a timeout, disconnect or task abort) can crash the host. Standalone CLI use that never drops async calls mid-flight is less exposed. Versions outside the two affected ranges are not affected.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.00071,"input_tokens":4166,"output_tokens":586,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-119142':13A,16A '-2026':12A,15A '46.0.0':26B,68C '48.0.6':28B,70C '49.0.0':30B,72C '49.0.3':32B,74C 'async':5A,41B,89C 'attack':50B 'call':6A,40B,58B,88C,120C 'cancel':56B,118C 'caus':63B 'cleanup':101C 'code':102C 'contain':75C 'crash':59B,115C 'cve':11A,14A 'denial':64B,77C 'drop':2A,43B,82C 'embedd':17B,55B,116C 'error':114C 'futur':36B,84C 'guest':46B,96C 'host':10A,61B,93C 'item':109C 'locat':106C 'make':53B 'one':105C 'panic':8A,33B,91C 'pend':4A,57B,119C 'plugin':22B 'process':62B 'result':113C 'return':37B,85C 'runtim':18B 'rust':19B 'search':103C 'servic':66B,79C 'start':48B,100C 'task':47B,97C 'typedfunc':39B,87C 'unwrap':111C 'version':25B 'vulner':80C 'wasm':21B 'wasm-plugin':20B 'wasmtim':1A,23B,24B,67C 'work':108C","nicknames":[],"mitigations":[],"who_affected":"Applications that embed Wasmtime and call async typed functions, where cancelling a pending call (through a timeout, disconnect or task abort) can crash the host. Standalone CLI use that never drops async calls mid-flight is less exposed. Versions outside the two affected ranges are not affected.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"first_public_at":"2026-10-29T16:18:07+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/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-2026-119142","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-119142","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"}