{"id":"CVE-2026-111923","kind":"vulnerability","aliases":["CVE-2026-111923"],"related":[],"title":"Fleet MDM server: crafted enrollment plist crashes server via recursion","description":"Fleet before 4.89.0 contains an unbounded recursion vulnerability in Apple MDM enrollment property list parsing that allows unauthenticated attackers to crash the server. Attackers can send a crafted binary plist payload of about 150 bytes to the enrollment endpoints, triggering exponential allocation or infinite recursion that exhausts CPU and memory.","summary":"Fleet before 4.89.0 parses Apple MDM enrollment/check-in property lists with unbounded recursion. An unauthenticated attacker with network access can send a ~150-byte binary plist to the enrollment endpoints and crash the server through CPU and memory exhaustion. Availability only. Only instances with Apple MDM enabled are affected.","severity":"high","cvss":8.7,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"fleet","fixed":["4.89.0"],"affected":"< 4.89.0","ecosystem":"go"}],"ecosystems":[],"tags":["apple-mdm","dos","fleet","other","self-hosted"],"not_affected_if":["apple-mdm-disabled","fleet-version-4.89.0-or-later","managed-hosting","no-apple-mdm-enrollment"],"how_to_check":"Check your Fleet version (fleet version, or the version shown in the UI); anything below 4.89.0 is affected. Then check whether Apple MDM is enabled (Settings > Integrations > MDM) and whether /api/mdm/apple/enroll and /api/mdm/apple/account_driven_enroll are reachable from untrusted networks.","fix":"Upgrade Fleet to 4.89.0 or later (4.92.0 also moves the fix into upstream micromdm/plist v0.3.0). Workaround: restrict network access to /api/mdm/apple/enroll and /api/mdm/apple/account_driven_enroll to trusted networks; request size limits do not help.","status":"open","published_at":"2026-10-17T19:16:35+00:00","first_seen_at":"2026-10-23T21:57:14+00:00","triaged_at":"2026-10-23T22:37:34+00:00","updated_at":"2026-10-24T00:23:31+00:00","category":"other","confidence":0.9,"triage":{"at":"2026-10-23T22:37:34Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade Fleet to 4.89.0 or later.","reach":"internet","title":"Fleet MDM server: crafted enrollment plist crashes server via recursion","impact":"low","summary":"Fleet versions before 4.89.0 parse Apple MDM enrollment property lists without bounding recursion. An unauthenticated attacker can send a roughly 150-byte binary plist to the enrollment endpoints to exhaust CPU and memory and crash the server.","category":"other","who_cares":["fleet","apple-mdm","self-hosted"],"confidence":0.7,"needs_auth":"no","worst_case":"Unauthenticated denial of service crashing the Fleet server","analyst_note":"Confirm the affected Fleet version range and whether the enrollment endpoints are exposed by default at https://nvd.nist.gov/vuln/detail/CVE-2026-111923 and the Fleet release notes.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["no-apple-mdm-enrollment","fleet-version-4.89.0-or-later"],"user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000501,"input_tokens":2942,"output_tokens":414,"severity_before":"high"},"analyst_status":"done","analyst_note":"Confirm the affected Fleet version range and whether the enrollment endpoints are exposed by default at https://nvd.nist.gov/vuln/detail/CVE-2026-111923 and the Fleet release notes.","search":"'-111923':13A,16A '-2026':12A,15A '150':48B,108C '4.89.0':29B,77C 'access':44B 'affect':74B 'alloc':116C 'allow':91C 'appl':19B,31B,70B,84C 'apple-mdm':18B 'attack':41B,93C,98C 'avail':65B 'binari':50B,103C 'byte':49B,109C 'contain':78C 'cpu':61B,122C 'craft':4A,102C 'crash':7A,57B,95C 'cve':11A,14A 'dos':21B 'enabl':72B 'endpoint':55B,113C 'enrol':5A,54B,86C,112C 'enrollment/check-in':33B 'exhaust':64B,121C 'exponenti':115C 'fleet':1A,17A,22B,27B,75C 'host':26B 'infinit':118C 'instanc':68B 'list':35B,88C 'mdm':2A,20B,32B,71B,85C 'memori':63B,124C 'network':43B 'pars':30B,89C 'payload':105C 'plist':6A,51B,104C 'properti':34B,87C 'recurs':10A,38B,81C,119C 'self':25B 'self-host':24B 'send':46B,100C 'server':3A,8A,59B,97C 'trigger':114C 'unauthent':40B,92C 'unbound':37B,80C 'via':9A 'vulner':82C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-17T19:16:35+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/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-2026-111923","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-111923","severity":null,"published_at":"2026-10-17T19:16:35+00:00","modified_at":"2026-10-19T21:14:14+00:00","first_seen_at":"2026-10-23T21:57:14+00:00","fetched_at":"2026-10-23T22:28:55+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-111923:651","url":null,"severity":null,"published_at":"2026-10-24T00:23:31+00:00","modified_at":"2026-10-24T00:23:31+00:00","first_seen_at":"2026-10-24T00:23:31+00:00","fetched_at":"2026-10-24T00:23:31+00:00","note":"Read Fleet GHSA-x467-vgxf-2g6h (primary) plus VulnCheck/CVE record. Only Apple MDM-enabled instances affected; no exploitation or PoC found; X count 3, no useful posts saved."}],"documents":[{"id":2581,"url":"https://github.com/fleetdm/fleet/security/advisories/GHSA-x467-vgxf-2g6h","title":"Fleet GHSA-x467-vgxf-2g6h: unbounded recursion in Apple MDM enrollment plist parsing","kind":"advisory","source":"analyst","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":null},{"id":2582,"url":"https://www.vulncheck.com/advisories/fleet-before-4.89.0-unauthenticated-dos-via-apple-mdm-enrollment-plist-parsing","title":"VulnCheck: Fleet before 4.89.0 Unauthenticated DoS via Apple MDM Enrollment Plist Parsing","kind":"advisory","source":"analyst","text":null,"published_at":null,"relation":"describes","confidence":null,"note":null}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}