{"id":"CVE-2026-101784","kind":"vulnerability","aliases":["CVE-2026-101784"],"related":[],"title":"MySQL Server optimizer flaw lets a privileged user crash the database","description":"Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: Optimizer).  Supported versions that are affected are MySQL Server: 8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1; MySQL Cluster: 8.0.0-8.0.49, 8.4.0-8.4.12, 9.7.0-9.7.3 and  26.7.0-26.7.1. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server, MySQL Cluster.  Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server, MySQL Cluster. CVSS 3.1 Base Score 4.9 (Availability impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).","summary":"A flaw in the MySQL Server optimizer lets a high-privileged user over the network cause a hang or repeatable crash of MySQL Server and MySQL Cluster. The sources describe only denial of service, with no code execution or data disclosure.","severity":"medium","cvss":4.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["database","mysql","package","self-hosted"],"not_affected_if":["auth-required","default-config"],"how_to_check":"- Run `SELECT VERSION();` on each MySQL Server and MySQL Cluster node and compare against the affected ranges: MySQL Server 8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1; MySQL Cluster 8.0.0-8.0.49, 8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1.","fix":"- Move MySQL Server and MySQL Cluster to a patched release from Oracle's July 2026 Critical Patch Update, as listed in the Oracle advisory (exact fixed versions unknown from these sources).","status":"open","published_at":"2026-10-20T22:18:34+00:00","first_seen_at":"2026-10-23T21:57:23+00:00","triaged_at":"2026-10-25T04:31:17+00:00","updated_at":"2026-10-25T04:31:17+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-25T04:31:17Z","model":"claude-haiku-5-5","output":{"fix":"- Move MySQL Server and MySQL Cluster to a patched release from Oracle's July 2026 Critical Patch Update, as listed in the Oracle advisory (exact fixed versions unknown from these sources).","reach":"network","title":"MySQL Server optimizer flaw lets a privileged user crash the database","impact":"low","summary":"A flaw in the MySQL Server optimizer lets a high-privileged user over the network cause a hang or repeatable crash of MySQL Server and MySQL Cluster. The sources describe only denial of service, with no code execution or data disclosure.","category":"package","nicknames":[],"who_cares":["mysql","self-hosted","database"],"confidence":0.7,"needs_auth":"yes","worst_case":"Database server hangs or crashes repeatedly, causing a full denial of service.","analyst_note":"Confirm the fixed MySQL versions for each branch in Oracle's July 2026 CPU advisory, since the sources give only affected ranges.","how_to_check":"- Run `SELECT VERSION();` on each MySQL Server and MySQL Cluster node and compare against the affected ranges: MySQL Server 8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1; MySQL Cluster 8.0.0-8.0.49, 8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1.","needs_analyst":true,"not_affected_if":["auth-required","default-config"],"who_is_affected":"Teams running MySQL Server or MySQL Cluster in the listed version ranges are exposed. The attacker needs high privileges on the database and network access to it, so databases reachable only by trusted administrators carry less risk. Systems on unaffected versions can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000689,"input_tokens":3585,"output_tokens":660,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-101784':14A,17A '-2026':13A,16A '/av':160C '26.7.0':92C,103C '26.7.1':93C,104C '3.1':150C,159C '4.9':153C '8.0.0':96C '8.0.49':97C '8.4.0':88C,98C '8.4.12':89C,99C '9.7.0':90C,100C '9.7.3':91C,101C 'abil':133C 'access':114C 'affect':84C 'allow':108C 'attack':111C,125C 'avail':154C 'base':151C 'caus':40B,135C 'cluster':51B,72C,95C,123C,148C 'code':61B 'complet':142C 'compon':77C 'compromis':119C 'crash':9A,45B,141C 'cve':12A,15A 'cvss':149C,156C,158C 'data':64B 'databas':11A,18B 'denial':56B 'describ':54B 'disclosur':65B 'dos':143C 'easili':105C 'execut':62B 'exploit':106C 'flaw':4A,25B 'frequent':139C 'h':168C 'h/ui':163C 'hang':42B,137C 'high':34B,109C 'high-privileg':33B 'host':23B 'impact':155C 'l/pr':162C 'let':5A,31B 'multipl':116C 'mysql':1A,19B,28B,47B,50B,69C,71C,76C,86C,94C,120C,122C,145C,147C 'n/a':167C 'n/ac':161C 'n/i':166C 'n/s':164C 'network':39B,113C 'optim':3A,30B,79C 'oracl':75C 'packag':20B 'privileg':7A,35B,110C 'product':73C 'protocol':117C 'repeat':44B,140C 'result':130C 'score':152C 'self':22B 'self-host':21B 'server':2A,29B,48B,70C,78C,87C,121C,146C 'servic':58B 'sourc':53B 'success':124C 'support':80C 'u/c':165C 'unauthor':132C 'user':8A,36B 'vector':157C 'version':81C 'via':115C 'vulner':66C,107C,128C","nicknames":[],"mitigations":[],"who_affected":"Teams running MySQL Server or MySQL Cluster in the listed version ranges are exposed. The attacker needs high privileges on the database and network access to it, so databases reachable only by trusted administrators carry less risk. Systems on unaffected versions can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T22:18:34+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","cvss_by":"secalert_us@oracle.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-101784","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-101784","severity":null,"published_at":"2026-10-20T22:18:34+00:00","modified_at":"2026-10-22T18:17:23+00:00","first_seen_at":"2026-10-23T21:57:23+00:00","fetched_at":"2026-10-23T22:28:59+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"}