{"id":"CVE-2026-119132","kind":"vulnerability","aliases":["CVE-2026-119132"],"related":[],"title":"Wasmtime: overlapping strings in fused adapters let a guest crash the host","description":"Wasmtime from 49.0.0 before 49.0.3 contains a denial-of-service vulnerability that allows a WebAssembly guest to trigger a host panic by transcoding overlapping strings in fused adapters. Attackers can make a same-instance component-to-component call transferring a string whose source and destination alias each other, crashing the host instead of raising a trap.","summary":"Wasmtime from 49.0.0 before 49.0.3 panics the host when a WebAssembly guest transfers a string whose source and destination overlap during a same-instance component call. The result is a denial of service: the host process crashes instead of raising a trap.","severity":"medium","cvss":5.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["component-model","runtime","wasmtime","webassembly"],"not_affected_if":["not-on-affected-versions","trusted-modules-only"],"how_to_check":"- Check the Wasmtime version in your build or lockfile; affected versions are `49.0.0` up to but not including `49.0.3`.\n- Find where Wasmtime is embedded in your services and whether it runs untrusted WebAssembly components.","fix":"- Wasmtime: move to `49.0.3` or later.","status":"open","published_at":"2026-10-29T16:18:06+00:00","first_seen_at":"2026-10-29T16:25:58+00:00","triaged_at":"2026-10-29T16:31:42+00:00","updated_at":"2026-10-29T16:31:42+00:00","category":"runtime","confidence":0.7,"triage":{"at":"2026-10-29T16:31:42Z","model":"claude-haiku-5-5","output":{"fix":"- Wasmtime: move to `49.0.3` or later.","reach":"unknown","title":"Wasmtime: overlapping strings in fused adapters let a guest crash the host","impact":"low","summary":"Wasmtime from 49.0.0 before 49.0.3 panics the host when a WebAssembly guest transfers a string whose source and destination overlap during a same-instance component call. The result is a denial of service: the host process crashes instead of raising a trap.","audience":"developers","category":"runtime","nicknames":[],"who_cares":["wasmtime","webassembly","component-model"],"confidence":0.7,"fix_status":"available","needs_auth":"unknown","worst_case":"host process crashes, causing denial of service","analyst_note":"","how_to_check":"- Check the Wasmtime version in your build or lockfile; affected versions are `49.0.0` up to but not including `49.0.3`.\n- Find where Wasmtime is embedded in your services and whether it runs untrusted WebAssembly components.","plain_action":"","needs_analyst":false,"not_affected_if":["trusted-modules-only","not-on-affected-versions"],"who_is_affected":"Teams that embed Wasmtime to run WebAssembly components, especially where guest code is untrusted, such as plugin systems or multi-tenant runtimes. Exposure depends on the component-model fused adapter path with aliasing strings; applications that run only trusted modules are lower risk.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000684,"input_tokens":4159,"output_tokens":537,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-119132':15A,18A '-2026':14A,17A '49.0.0':27B,70C '49.0.3':29B,72C 'adapt':6A,96C 'alia':116C 'allow':81C 'attack':97C 'call':51B,108C 'compon':20B,50B,105C,107C 'component-model':19B 'component-to-compon':104C 'contain':73C 'crash':10A,62B,119C 'cve':13A,16A 'denial':56B,76C 'denial-of-servic':75C 'destin':43B,115C 'fuse':5A,95C 'guest':9A,36B,84C 'host':12A,32B,60B,88C,121C 'instanc':49B,103C 'instead':63B,122C 'let':7A 'make':99C 'model':21B 'overlap':2A,44B,92C 'panic':30B,89C 'process':61B 'rais':65B,124C 'result':53B 'runtim':22B 'same-inst':47B,101C 'servic':58B,78C 'sourc':41B,113C 'string':3A,39B,93C,111C 'transcod':91C 'transfer':37B,109C 'trap':67B,126C 'trigger':86C 'vulner':79C 'wasmtim':1A,23B,25B,68C 'webassembl':24B,35B,83C 'whose':40B,112C","nicknames":[],"mitigations":[],"who_affected":"Teams that embed Wasmtime to run WebAssembly components, especially where guest code is untrusted, such as plugin systems or multi-tenant runtimes. Exposure depends on the component-model fused adapter path with aliasing strings; applications that run only trusted modules are lower risk.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","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: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-2026-119132","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-119132","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"}