{"id":"CVE-2026-18633","kind":"vulnerability","aliases":["CVE-2026-18633"],"related":[],"title":"Synology DSM: uninitialized pointer in NFS daemon enables remote denial of service","description":"An access of uninitialized pointer vulnerability in the nfsd in Synology DiskStation Manager (DSM) before 7.3.2-86009-5 and 7.4.1-90080-1 allows remote attackers to conduct denial-of-service attacks.","summary":"Synology DiskStation Manager has an access of an uninitialized pointer in its nfsd NFS daemon. A remote attacker can crash the service and cause a denial of service.","severity":"high","cvss":7.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["dsm","infrastructure","nas","nfs","self-hosted","synology"],"not_affected_if":["nfs-disabled","not-network-reachable"],"how_to_check":"- Check the DSM version under Control Panel > Info Center (or `cat /etc/VERSION` on the NAS).\n- Check whether NFS is enabled under Control Panel > File Services > NFS.","fix":"- Move DSM to `7.3.2-86009-5` or later on the 7.3 branch.\n- Move DSM to `7.4.1-90080-1` or later on the 7.4 branch.","status":"open","published_at":"2026-11-12T04:17:19+00:00","first_seen_at":"2026-11-12T04:47:09+00:00","triaged_at":"2026-11-12T04:47:44+00:00","updated_at":"2026-11-12T04:47:44+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-11-12T04:47:44Z","model":"claude-haiku-5-5","output":{"fix":"- Move DSM to `7.3.2-86009-5` or later on the 7.3 branch.\n- Move DSM to `7.4.1-90080-1` or later on the 7.4 branch.","reach":"network","title":"Synology DSM: uninitialized pointer in NFS daemon enables remote denial of service","impact":"low","summary":"Synology DiskStation Manager has an access of an uninitialized pointer in its nfsd NFS daemon. A remote attacker can crash the service and cause a denial of service.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["synology","dsm","nas","nfs","self-hosted"],"confidence":0.6,"fix_status":"available","needs_auth":"unknown","worst_case":"remote attacker crashes the NFS service, denying availability","analyst_note":"","how_to_check":"- Check the DSM version under Control Panel > Info Center (or `cat /etc/VERSION` on the NAS).\n- Check whether NFS is enabled under Control Panel > File Services > NFS.","plain_action":"","product_name":"","needs_analyst":false,"not_affected_if":["nfs-disabled","not-network-reachable"],"who_is_affected":"Synology DSM installations running a version before 7.3.2-86009-5 or 7.4.1-90080-1 that expose the nfsd NFS service to the network are affected. Systems without NFS enabled, or not reachable from the network, are less exposed; the sources do not say more.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000728,"input_tokens":4542,"output_tokens":547,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-1':76C '-18633':15A,18A '-2026':14A,17A '-5':72C '-86009':71C '-90080':75C '7.3.2':70C '7.4.1':74C 'access':32B,56C 'allow':77C 'attack':44B,79C,86C 'caus':50B 'conduct':81C 'crash':46B 'cve':13A,16A 'daemon':7A,41B 'denial':10A,52B,83C 'denial-of-servic':82C 'diskstat':28B,66C 'dsm':2A,19B,68C 'enabl':8A 'host':25B 'infrastructur':20B 'manag':29B,67C 'nas':21B 'nfs':6A,22B,40B 'nfsd':39B,63C 'pointer':4A,36B,59C 'remot':9A,43B,78C 'self':24B 'self-host':23B 'servic':12A,48B,54B,85C 'synolog':1A,26B,27B,65C 'uniniti':3A,35B,58C 'vulner':60C","nicknames":[],"mitigations":[],"who_affected":"Synology DSM installations running a version before 7.3.2-86009-5 or 7.4.1-90080-1 that expose the nfsd NFS service to the network are affected. Systems without NFS enabled, or not reachable from the network, are less exposed; the sources do not say more.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["dsm","high","infrastructure","nas","nfs","selfhosted","synology"],"campaign_type":null,"search_a":"'-18633':15A,18A '-2026':14A,17A 'cve':13A,16A 'daemon':7A 'denial':10A 'dsm':2A 'enabl':8A 'nfs':6A 'pointer':4A 'remot':9A 'servic':12A 'synolog':1A 'uniniti':3A","search_b":"'access':32B 'attack':44B 'caus':50B 'crash':46B 'daemon':41B 'denial':52B 'diskstat':28B 'dsm':19B 'host':25B 'infrastructur':20B 'manag':29B 'nas':21B 'nfs':22B,40B 'nfsd':39B 'pointer':36B 'remot':43B 'self':24B 'self-host':23B 'servic':48B,54B 'synolog':26B,27B 'uniniti':35B","search_c":"'-1':76C '-5':72C '-86009':71C '-90080':75C '7.3.2':70C '7.4.1':74C 'access':56C 'allow':77C 'attack':79C,86C 'conduct':81C 'denial':83C 'denial-of-servic':82C 'diskstat':66C 'dsm':68C 'manag':67C 'nfsd':63C 'pointer':59C 'remot':78C 'servic':85C 'synolog':65C 'uniniti':58C 'vulner':60C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-12T04:17:19+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvss_by":"security@synology.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-18633","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-18633","severity":null,"published_at":"2026-11-12T04:17:19+00:00","modified_at":"2026-11-12T04:17:19+00:00","first_seen_at":"2026-11-12T04:47:09+00:00","fetched_at":"2026-11-12T04:47:09+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"}