{"id":"CVE-2026-117955","kind":"vulnerability","aliases":["CVE-2026-117955"],"related":[],"title":"Firefox: JIT miscompilation in WebAssembly component may allow code execution","description":"JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 159 and Firefox ESR 153.6.","summary":"A bug in Firefox's JavaScript JIT compiler, in the WebAssembly component, miscompiles code. The sources do not say what an attacker gets from it, beyond the miscompilation itself.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["browser","desktop","firefox","runtime"],"not_affected_if":["fixed-version"],"how_to_check":"- Check the installed Firefox version with `firefox --version` or Help > About Firefox; unknown whether earlier versions are affected beyond the fixed releases.","fix":"- Update Firefox to `159` or Firefox ESR to `153.6`, the versions the sources say fixed it.","status":"open","published_at":"2026-10-27T14:16:51+00:00","first_seen_at":"2026-10-27T14:32:23+00:00","triaged_at":"2026-10-27T14:35:33+00:00","updated_at":"2026-10-27T14:35:33+00:00","category":"runtime","confidence":0.5,"triage":{"at":"2026-10-27T14:35:33Z","model":"claude-haiku-5-5","output":{"fix":"- Update Firefox to `159` or Firefox ESR to `153.6`, the versions the sources say fixed it.","reach":"internet","title":"Firefox: JIT miscompilation in WebAssembly component may allow code execution","impact":"high","summary":"A bug in Firefox's JavaScript JIT compiler, in the WebAssembly component, miscompiles code. The sources do not say what an attacker gets from it, beyond the miscompilation itself.","category":"runtime","nicknames":[],"who_cares":["firefox","browser","desktop"],"confidence":0.5,"needs_auth":"unknown","worst_case":"unknown; sources do not describe the attacker's gain","analyst_note":"Check the Mozilla security advisory for the exploit path, impact and whether a web page alone triggers it; the NVD entry has no details.","how_to_check":"- Check the installed Firefox version with `firefox --version` or Help > About Firefox; unknown whether earlier versions are affected beyond the fixed releases.","needs_analyst":true,"not_affected_if":["fixed-version"],"who_is_affected":"Anyone running Firefox builds older than Firefox 159 or Firefox ESR 153.6. The sources do not say which configurations or content are needed to trigger it, so unknown whether a web page alone is enough.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000572,"input_tokens":3250,"output_tokens":494,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-117955':13A,16A '-2026':12A,15A '153.6':66C '159':62C 'allow':8A 'attack':42B 'beyond':46B 'browser':17B 'bug':22B 'code':9A,34B 'compil':28B 'compon':6A,32B,55C 'cve':11A,14A 'desktop':18B 'esr':65C 'execut':10A 'firefox':1A,19B,24B,61C,64C 'fix':59C 'get':43B 'javascript':26B,53C 'jit':2A,27B,49C 'may':7A 'miscompil':3A,33B,48B,50C 'runtim':20B 'say':39B 'sourc':36B 'vulner':57C 'webassembl':5A,31B,54C","nicknames":[],"mitigations":[],"who_affected":"Anyone running Firefox builds older than Firefox 159 or Firefox ESR 153.6. The sources do not say which configurations or content are needed to trigger it, so unknown whether a web page alone is enough.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T14:16:51+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-117955","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-117955","severity":null,"published_at":"2026-10-27T14:16:51+00:00","modified_at":"2026-10-27T14:16:51+00:00","first_seen_at":"2026-10-27T14:32:23+00:00","fetched_at":"2026-10-27T14:32:23+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"}