{"id":"CVE-2026-86981","kind":"vulnerability","aliases":["CVE-2026-86981"],"related":[],"title":"Apple macOS: out-of-bounds write lets an app crash the system","description":"An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in macOS Sequoia 15.8, macOS Tahoe 26.7. An app may be able to cause unexpected system termination.","summary":"An out-of-bounds write flaw in macOS allows a malicious app to cause an unexpected system termination. Apple fixed it with improved bounds checking in macOS Sequoia 15.8 and macOS Tahoe 26.7.","severity":"medium","cvss":5.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["apple-silicon","infrastructure","intel-mac","macos"],"not_affected_if":["already-patched"],"how_to_check":"- Run `sw_vers -productVersion` on each Mac and compare against `15.8` (Sequoia) or `26.7` (Tahoe)\n- Check the Apple security notes for the affected component: unknown","fix":"- Update macOS Sequoia to `15.8` or later\n- Update macOS Tahoe to `26.7` or later","status":"open","published_at":"2026-10-20T01:17:29+00:00","first_seen_at":"2026-10-23T21:57:19+00:00","triaged_at":"2026-10-25T04:12:32+00:00","updated_at":"2026-10-25T04:12:32+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-25T04:12:32Z","model":"claude-haiku-5-5","output":{"fix":"- Update macOS Sequoia to `15.8` or later\n- Update macOS Tahoe to `26.7` or later","reach":"local","title":"Apple macOS: out-of-bounds write lets an app crash the system","impact":"low","summary":"An out-of-bounds write flaw in macOS allows a malicious app to cause an unexpected system termination. Apple fixed it with improved bounds checking in macOS Sequoia 15.8 and macOS Tahoe 26.7.","category":"infrastructure","nicknames":[],"who_cares":["macos","apple-silicon","intel-mac"],"confidence":0.6,"needs_auth":"unknown","worst_case":"A malicious app crashes the system unexpectedly","analyst_note":"Check Apple's security release notes for the affected component and whether the flaw is reachable beyond a local app.","how_to_check":"- Run `sw_vers -productVersion` on each Mac and compare against `15.8` (Sequoia) or `26.7` (Tahoe)\n- Check the Apple security notes for the affected component: unknown","needs_analyst":true,"not_affected_if":["already-patched"],"who_is_affected":"Any Mac running macOS Sequoia before 15.8 or macOS Tahoe before 26.7 is exposed, since the flaw sits in the operating system and an app can trigger it. The sources do not name a specific configuration or role that narrows exposure. Machines already on the fixed releases can skip it.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.0006,"input_tokens":3277,"output_tokens":544,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-2026':15A,18A '-86981':16A,19A '15.8':57B,82C '26.7':61B,85C 'abl':90C 'address':70C 'allow':37B 'app':10A,40B,87C 'appl':1A,21B,47B 'apple-silicon':20B 'bound':6A,32B,52B,66C,73C 'caus':42B,92C 'check':53B,74C 'crash':11A 'cve':14A,17A 'fix':48B,78C 'flaw':34B 'improv':51B,72C 'infrastructur':23B 'intel':25B 'intel-mac':24B 'issu':68C,76C 'let':8A 'mac':26B 'maco':2A,27B,36B,55B,59B,80C,83C 'malici':39B 'may':88C 'out-of-bound':3A,29B,63C 'sequoia':56B,81C 'silicon':22B 'system':13A,45B,94C 'taho':60B,84C 'termin':46B,95C 'unexpect':44B,93C 'write':7A,33B,67C","nicknames":[],"mitigations":[],"who_affected":"Any Mac running macOS Sequoia before 15.8 or macOS Tahoe before 26.7 is exposed, since the flaw sits in the operating system and an app can trigger it. The sources do not name a specific configuration or role that narrows exposure. Machines already on the fixed releases can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T01:17:29+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvss_by":"134c704f-9b21-4f2e-91b3-4a467353bcc0","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-86981","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-86981","severity":null,"published_at":"2026-10-20T01:17:29+00:00","modified_at":"2026-10-20T15:03:59+00:00","first_seen_at":"2026-10-23T21:57:19+00:00","fetched_at":"2026-10-23T22:28:57+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"}