{"id":"CVE-2026-119141","kind":"vulnerability","aliases":["CVE-2026-119141"],"related":[],"title":"Wasmtime: malicious Wasm module can crash the host process","description":"Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a denial of service vulnerability that allows malicious Wasm modules to panic the host because the may_leave flag is not cleared during realloc. Attackers can call into the host from realloc while lowering stream or future results, such as cancelling the active read or re-waiting a waitable-set, crashing the host.","summary":"Wasmtime, a WebAssembly runtime, panics the host when a malicious Wasm module calls back into the host during a realloc while lowering stream or future results. An attacker who supplies a crafted module can crash the process that runs it, causing denial of service.","severity":"medium","cvss":6.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["plugin-hosts","runtime","rust","wasmtime","webassembly"],"not_affected_if":["trusted-modules-only","versions-outside-range"],"how_to_check":"- Check the Wasmtime version in your build or lockfile, for example `wasmtime --version` or the `wasmtime` crate version in `Cargo.lock`\n- Flag versions in the affected ranges: `46.0.0` to before `48.0.6`, and `49.0.0` to before `49.0.3`","fix":"- Upgrade to `48.0.6` on the 48 line\n- Upgrade to `49.0.3` 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":"2026-10-29T16:30:07+00:00","updated_at":"2026-10-29T16:30:07+00:00","category":"runtime","confidence":0.7,"triage":{"at":"2026-10-29T16:30:07Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade to `48.0.6` on the 48 line\n- Upgrade to `49.0.3` on the 49 line","reach":"unknown","title":"Wasmtime: malicious Wasm module can crash the host process","impact":"low","summary":"Wasmtime, a WebAssembly runtime, panics the host when a malicious Wasm module calls back into the host during a realloc while lowering stream or future results. An attacker who supplies a crafted module can crash the process that runs it, causing denial of service.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["wasmtime","webassembly","rust","plugin-hosts"],"confidence":0.7,"fix_status":"available","needs_auth":"unknown","worst_case":"Host process crashes, causing denial of service for the service running it","analyst_note":"","how_to_check":"- Check the Wasmtime version in your build or lockfile, for example `wasmtime --version` or the `wasmtime` crate version in `Cargo.lock`\n- Flag versions in the affected ranges: `46.0.0` to before `48.0.6`, and `49.0.0` to before `49.0.3`","plain_action":"","needs_analyst":false,"not_affected_if":["trusted-modules-only","versions-outside-range"],"who_is_affected":"Applications that embed Wasmtime and run untrusted or third-party WebAssembly modules are exposed, because a malicious module can trigger the panic from inside the host. Services that only run trusted, self-authored Wasm modules face much lower risk. Teams on Wasmtime versions outside the affected ranges can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000716,"input_tokens":4176,"output_tokens":596,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-119141':12A,15A '-2026':11A,14A '46.0.0':68C '48.0.6':70C '49.0.0':72C '49.0.3':74C 'activ':118C 'allow':82C 'attack':50B,100C 'back':36B 'call':35B,102C 'cancel':116C 'caus':63B 'clear':97C 'contain':75C 'craft':54B 'crash':6A,57B,128C 'cve':10A,13A 'denial':64B,77C 'flag':94C 'futur':47B,112C 'host':8A,18B,29B,39B,89C,105C,130C 'leav':93C 'lower':44B,109C 'malici':2A,32B,83C 'may':92C 'modul':4A,34B,55B,85C 'panic':27B,87C 'plugin':17B 'plugin-host':16B 'process':9A,59B 're':122C 're-wait':121C 'read':119C 'realloc':42B,99C,107C 'result':48B,113C 'run':61B 'runtim':19B,26B 'rust':20B 'servic':66B,79C 'set':127C 'stream':45B,110C 'suppli':52B 'vulner':80C 'wait':123C 'waitabl':126C 'waitable-set':125C 'wasm':3A,33B,84C 'wasmtim':1A,21B,23B,67C 'webassembl':22B,25B","nicknames":[],"mitigations":[],"who_affected":"Applications that embed Wasmtime and run untrusted or third-party WebAssembly modules are exposed, because a malicious module can trigger the panic from inside the host. Services that only run trusted, self-authored Wasm modules face much lower risk. Teams on Wasmtime versions outside the affected ranges can skip it.","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: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-2026-119141","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-119141","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"}