{"id":"CVE-2026-115385","kind":"vulnerability","aliases":["CVE-2026-115385"],"related":[],"title":"Wasmtime: guest timestamp calls crash the host process on Unix","description":"Wasmtime 46.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains a denial of service vulnerability in the wasmtime-wasi WASIp3 implementation that allows guests to abort the Unix host process. Guests with mutable preopened directory access can call set-times or set-times-at with negative seconds timestamps before the epoch, triggering an assertion failure that crashes the host.","summary":"Wasmtime's WASIp3 implementation in wasmtime-wasi asserts when a guest passes a negative (pre-epoch) seconds value to set-times or set-times-at. A guest with mutable preopened directory access can use this to abort the host process.","severity":"medium","cvss":6.9,"epss":0.00112,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["runtime","self-hosted","unix","wasmtime","webassembly"],"not_affected_if":["default-config","no-preopened-dirs","trusted-guests-only"],"how_to_check":"- Run `wasmtime --version` and compare against the affected ranges: 46.0.0 before 48.0.4 and 49.0.0 before 49.0.2.\n- Check whether your application uses the wasmtime-wasi WASIp3 preview with mutable preopened directories.","fix":"- Upgrade Wasmtime to `48.0.4` or `49.0.2` (or a later release in the same line).","status":"open","published_at":"2026-10-22T19:17:45+00:00","first_seen_at":"2026-10-23T21:57:31+00:00","triaged_at":"2026-10-25T03:38:48+00:00","updated_at":"2026-10-25T03:38:48+00:00","category":"runtime","confidence":0.7,"triage":{"at":"2026-10-25T03:38:48Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Wasmtime to `48.0.4` or `49.0.2` (or a later release in the same line).","reach":"local","title":"Wasmtime: guest timestamp calls crash the host process on Unix","impact":"low","summary":"Wasmtime's WASIp3 implementation in wasmtime-wasi asserts when a guest passes a negative (pre-epoch) seconds value to set-times or set-times-at. A guest with mutable preopened directory access can use this to abort the host process.","category":"runtime","nicknames":[],"who_cares":["wasmtime","webassembly","unix","self-hosted"],"confidence":0.7,"needs_auth":"unknown","worst_case":"a guest crashes the Unix host process via assertion failure","analyst_note":"","how_to_check":"- Run `wasmtime --version` and compare against the affected ranges: 46.0.0 before 48.0.4 and 49.0.0 before 49.0.2.\n- Check whether your application uses the wasmtime-wasi WASIp3 preview with mutable preopened directories.","needs_analyst":false,"not_affected_if":["default-config","no-preopened-dirs","trusted-guests-only"],"who_is_affected":"Teams that embed Wasmtime on Unix and run untrusted or third-party WebAssembly guests that have been granted mutable preopened directory access through WASIp3. A host that only runs trusted guests, or grants no preopened directories, is much less exposed. Hosts on the affected version ranges with no WASIp3 usage can deprioritise this.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000628,"input_tokens":3412,"output_tokens":573,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-115385':13A,16A '-2026':12A,15A '46.0.0':69C '48.0.4':71C '49.0.0':73C '49.0.2':75C 'abort':64B,93C 'access':59B,103C 'allow':90C 'assert':32B,123C 'call':4A,105C 'contain':76C 'crash':5A,126C 'cve':11A,14A 'denial':78C 'directori':58B,102C 'epoch':41B,120C 'failur':124C 'guest':2A,35B,54B,91C,98C 'host':7A,20B,66B,96C,128C 'implement':27B,88C 'mutabl':56B,100C 'negat':38B,115C 'pass':36B 'pre':40B 'pre-epoch':39B 'preopen':57B,101C 'process':8A,67B,97C 'runtim':17B 'second':42B,116C 'self':19B 'self-host':18B 'servic':80C 'set':46B,50B,107C,111C 'set-tim':45B,106C 'set-times-at':49B,110C 'time':47B,51B,108C,112C 'timestamp':3A,117C 'trigger':121C 'unix':10A,21B,95C 'use':61B 'valu':43B 'vulner':81C 'wasi':31B,86C 'wasip3':26B,87C 'wasmtim':1A,22B,24B,30B,68C,85C 'wasmtime-wasi':29B,84C 'webassembl':23B","nicknames":[],"mitigations":[],"who_affected":"Teams that embed Wasmtime on Unix and run untrusted or third-party WebAssembly guests that have been granted mutable preopened directory access through WASIp3. A host that only runs trusted guests, or grants no preopened directories, is much less exposed. Hosts on the affected version ranges with no WASIp3 usage can deprioritise this.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-22T19:17:45+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/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-2026-115385","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-115385","severity":null,"published_at":"2026-10-22T19:17:45+00:00","modified_at":"2026-10-22T19:17:45+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-2026-115385","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-115385","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"}