{"id":"CVE-2026-115390","kind":"vulnerability","aliases":["CVE-2026-115390"],"related":[],"title":"Wasmtime: fuel accounting flaw lets guest code evade timeouts","description":"Wasmtime 47.0.0 before 48.0.3 and 49.0.0 before 49.0.1 contains a fuel accounting flaw in Cranelift-compiled call_ref and try_table catch paths. Malicious guests can reset consumed fuel after calls to run exponentially long on linear fuel, evading timeouts and periodic yields for denial of service.","summary":"Wasmtime versions 47.0.0 before 48.0.3 and 49.0.0 before 49.0.1 miscount consumed fuel in Cranelift-compiled call_ref and try_table catch paths. A malicious WebAssembly guest can reset its fuel after calls and run far longer than its limit, causing denial of service.","severity":"medium","cvss":6.9,"epss":0.00184,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["multi-tenant","plugin-systems","runtime","wasmtime","webassembly"],"not_affected_if":["trusted-guests-only","wasmtime-not-used"],"how_to_check":"- Check the Wasmtime version in the project lockfile or with `wasmtime --version`\n- Look for embedders that set fuel limits or epoch-based timeouts on untrusted guest code","fix":"- Upgrade Wasmtime to `48.0.3` on the 48 line or `49.0.1` on the 49 line\n- Versions 47.x need an upgrade to a fixed release; check the advisory for the exact 47 fix if unknown","status":"open","published_at":"2026-10-22T19:17:46+00:00","first_seen_at":"2026-10-23T21:57:31+00:00","triaged_at":"2026-10-25T03:38:44+00:00","updated_at":"2026-10-25T03:38:44+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-10-25T03:38:44Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Wasmtime to `48.0.3` on the 48 line or `49.0.1` on the 49 line\n- Versions 47.x need an upgrade to a fixed release; check the advisory for the exact 47 fix if unknown","reach":"unknown","title":"Wasmtime: fuel accounting flaw lets guest code evade timeouts","impact":"low","summary":"Wasmtime versions 47.0.0 before 48.0.3 and 49.0.0 before 49.0.1 miscount consumed fuel in Cranelift-compiled call_ref and try_table catch paths. A malicious WebAssembly guest can reset its fuel after calls and run far longer than its limit, causing denial of service.","category":"runtime","nicknames":[],"who_cares":["wasmtime","webassembly","plugin-systems","multi-tenant"],"confidence":0.6,"needs_auth":"unknown","worst_case":"Untrusted guest code evades fuel limits and stalls the host process","analyst_note":"Confirm the 47.x fixed version and whether fuel-based limits are the default protection the advisory expects; sources give only NVD and EPSS.","how_to_check":"- Check the Wasmtime version in the project lockfile or with `wasmtime --version`\n- Look for embedders that set fuel limits or epoch-based timeouts on untrusted guest code","needs_analyst":true,"not_affected_if":["trusted-guests-only","wasmtime-not-used"],"who_is_affected":"Applications that embed Wasmtime and run untrusted WebAssembly guest modules, such as plugin systems or multi-tenant function runtimes, depend on fuel and timeouts to bound guest work. Hosts that only run their own trusted Wasm code or do not use Wasmtime can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000669,"input_tokens":3402,"output_tokens":657,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-115390':12A,15A '-2026':11A,14A '47.0.0':27B,70C '48.0.3':29B,72C '49.0.0':31B,74C '49.0.1':33B,76C 'account':3A,80C 'call':41B,57B,86C,100C 'catch':46B,91C 'caus':65B 'code':7A 'compil':40B,85C 'consum':35B,97C 'contain':77C 'cranelift':39B,84C 'cranelift-compil':38B,83C 'cve':10A,13A 'denial':66B,114C 'evad':8A,108C 'exponenti':103C 'far':60B 'flaw':4A,81C 'fuel':2A,36B,55B,79C,98C,107C 'guest':6A,51B,94C 'let':5A 'limit':64B 'linear':106C 'long':104C 'longer':61B 'malici':49B,93C 'miscount':34B 'multi':17B 'multi-ten':16B 'path':47B,92C 'period':111C 'plugin':20B 'plugin-system':19B 'ref':42B,87C 'reset':53B,96C 'run':59B,102C 'runtim':22B 'servic':68B,116C 'system':21B 'tabl':45B,90C 'tenant':18B 'timeout':9A,109C 'tri':44B,89C 'version':26B 'wasmtim':1A,23B,25B,69C 'webassembl':24B,50B 'yield':112C","nicknames":[],"mitigations":[],"who_affected":"Applications that embed Wasmtime and run untrusted WebAssembly guest modules, such as plugin systems or multi-tenant function runtimes, depend on fuel and timeouts to bound guest work. Hosts that only run their own trusted Wasm code or do not use Wasmtime can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-22T19:17:46+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/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-2026-115390","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-115390","severity":null,"published_at":"2026-10-22T19:17:46+00:00","modified_at":"2026-10-23T15:17:29+00:00","first_seen_at":"2026-10-23T21:57:31+00:00","fetched_at":"2026-10-23T22:29:02+00:00","note":null},{"source":"epss","external_id":"CVE-2026-115390","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-115390","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T07:15:51+00:00","fetched_at":"2026-10-24T07:15:51+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"}