{"id":"CVE-2026-85101","kind":"vulnerability","aliases":["CVE-2026-85101"],"related":[],"title":"Synology DiskStation: rsync auth bypass lets remote attackers read and write files","description":"An authentication bypass using an alternate path or channel vulnerability in the rsync in Synology DiskStation Manager (DSM) before 7.2.1-69057-13, 7.2.2-72806-10, 7.3.2-86009-5, and 7.4.1-90080-1 allows remote attackers to read specific files, write arbitrary files, and conduct limited denial-of-service attacks.","summary":"The rsync service in Synology DiskStation Manager has an authentication bypass through an alternate path or channel. A remote attacker can read specific files, write arbitrary files, and cause limited denial of service.","severity":"high","cvss":8.6,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["dsm","infrastructure","nas","rsync","self-hosted","synology"],"not_affected_if":["patched-dsm","rsync-disabled"],"how_to_check":"- Check the installed DSM version in Control Panel > Info Center; compare it with the fixed versions below.\n- Check whether the rsync service is enabled in Control Panel > File Services > rsync.","fix":"- Upgrade DSM to `7.2.1-69057-13` or later on the 7.2.1 branch\n- Upgrade DSM to `7.2.2-72806-10` or later on the 7.2.2 branch\n- Upgrade DSM to `7.3.2-86009-5` or later on the 7.3.2 branch\n- Upgrade DSM to `7.4.1-90080-1` or later on the 7.4.1 branch","status":"open","published_at":"2026-11-12T04:17:21+00:00","first_seen_at":"2026-11-12T04:47:10+00:00","triaged_at":"2026-11-12T04:47:39+00:00","updated_at":"2026-11-12T04:47:39+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-11-12T04:47:39Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade DSM to `7.2.1-69057-13` or later on the 7.2.1 branch\n- Upgrade DSM to `7.2.2-72806-10` or later on the 7.2.2 branch\n- Upgrade DSM to `7.3.2-86009-5` or later on the 7.3.2 branch\n- Upgrade DSM to `7.4.1-90080-1` or later on the 7.4.1 branch","reach":"network","title":"Synology DiskStation: rsync auth bypass lets remote attackers read and write files","impact":"high","summary":"The rsync service in Synology DiskStation Manager has an authentication bypass through an alternate path or channel. A remote attacker can read specific files, write arbitrary files, and cause limited denial of service.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["synology","dsm","rsync","nas","self-hosted"],"confidence":0.6,"fix_status":"available","needs_auth":"unknown","worst_case":"Attacker reads specific files and writes arbitrary files on the NAS","analyst_note":"Check the Synology security advisory for this CVE to confirm the rsync exposure conditions and whether authentication is needed.","how_to_check":"- Check the installed DSM version in Control Panel > Info Center; compare it with the fixed versions below.\n- Check whether the rsync service is enabled in Control Panel > File Services > rsync.","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["rsync-disabled","patched-dsm"],"who_is_affected":"Synology NAS devices running DSM with the rsync service enabled are exposed. A device with rsync turned off or not reachable from the network is not exposed through this flaw. The sources do not say whether the attack needs credentials.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000786,"input_tokens":4581,"output_tokens":655,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-1':91C '-10':84C '-13':81C '-2026':14A,17A '-5':87C '-69057':80C '-72806':83C '-85101':15A,18A '-86009':86C '-90080':90C '7.2.1':79C '7.2.2':82C '7.3.2':85C '7.4.1':89C 'allow':92C 'altern':40B,65C 'arbitrari':52B,100C 'attack':8A,46B,94C,109C 'auth':4A 'authent':36B,61C 'bypass':5A,37B,62C 'caus':55B 'channel':43B,68C 'conduct':103C 'cve':13A,16A 'denial':57B,106C 'denial-of-servic':105C 'diskstat':2A,32B,75C 'dsm':19B,77C 'file':12A,50B,53B,98C,101C 'host':25B 'infrastructur':20B 'let':6A 'limit':56B,104C 'manag':33B,76C 'nas':21B 'path':41B,66C 'read':9A,48B,96C 'remot':7A,45B,93C 'rsync':3A,22B,28B,72C 'self':24B 'self-host':23B 'servic':29B,59B,108C 'specif':49B,97C 'synolog':1A,26B,31B,74C 'use':63C 'vulner':69C 'write':11A,51B,99C","nicknames":[],"mitigations":[],"who_affected":"Synology NAS devices running DSM with the rsync service enabled are exposed. A device with rsync turned off or not reachable from the network is not exposed through this flaw. The sources do not say whether the attack needs credentials.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["dsm","high","infrastructure","nas","rsync","selfhosted","synology"],"campaign_type":null,"search_a":"'-2026':14A,17A '-85101':15A,18A 'attack':8A 'auth':4A 'bypass':5A 'cve':13A,16A 'diskstat':2A 'file':12A 'let':6A 'read':9A 'remot':7A 'rsync':3A 'synolog':1A 'write':11A","search_b":"'altern':40B 'arbitrari':52B 'attack':46B 'authent':36B 'bypass':37B 'caus':55B 'channel':43B 'denial':57B 'diskstat':32B 'dsm':19B 'file':50B,53B 'host':25B 'infrastructur':20B 'limit':56B 'manag':33B 'nas':21B 'path':41B 'read':48B 'remot':45B 'rsync':22B,28B 'self':24B 'self-host':23B 'servic':29B,59B 'specif':49B 'synolog':26B,31B 'write':51B","search_c":"'-1':91C '-10':84C '-13':81C '-5':87C '-69057':80C '-72806':83C '-86009':86C '-90080':90C '7.2.1':79C '7.2.2':82C '7.3.2':85C '7.4.1':89C 'allow':92C 'altern':65C 'arbitrari':100C 'attack':94C,109C 'authent':61C 'bypass':62C 'channel':68C 'conduct':103C 'denial':106C 'denial-of-servic':105C 'diskstat':75C 'dsm':77C 'file':98C,101C 'limit':104C 'manag':76C 'path':66C 'read':96C 'remot':93C 'rsync':72C 'servic':108C 'specif':97C 'synolog':74C 'use':63C 'vulner':69C 'write':99C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-12T04:17:21+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L","cvss_by":"security@synology.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-85101","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-85101","severity":null,"published_at":"2026-11-12T04:17:21+00:00","modified_at":"2026-11-12T04:17:21+00:00","first_seen_at":"2026-11-12T04:47:10+00:00","fetched_at":"2026-11-12T04:47:10+00:00","note":null}],"documents":[],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}