{"id":"CVE-2026-101731","kind":"vulnerability","aliases":["CVE-2026-101731"],"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 with network access hang or repeatedly crash MySQL Server and MySQL Cluster. The sources describe only a denial of service, with no code execution or data theft.","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","version-outside-range"],"how_to_check":"- Run `SELECT VERSION();` on the MySQL server and compare against the affected ranges: MySQL Server 8.4.0 to 8.4.12, 9.7.0 to 9.7.3, 26.7.0 to 26.7.1; MySQL Cluster 8.0.0 to 8.0.49, 8.4.0 to 8.4.12, 9.7.0 to 9.7.3, 26.7.0 to 26.7.1.","fix":null,"status":"open","published_at":"2026-10-20T22:18:27+00:00","first_seen_at":"2026-10-23T21:57:23+00:00","triaged_at":"2026-10-25T04:31:25+00:00","updated_at":"2026-10-25T04:31:25+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-25T04:31:25Z","model":"claude-haiku-5-5","output":{"fix":"unknown","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 with network access hang or repeatedly crash MySQL Server and MySQL Cluster. The sources describe only a denial of service, with no code execution or data theft.","category":"package","nicknames":[],"who_cares":["mysql","self-hosted","database"],"confidence":0.6,"needs_auth":"yes","worst_case":"Database server hangs or crashes repeatedly, causing denial of service","analyst_note":"Check the Oracle Critical Patch Update advisory for the fixed versions, since the sources list affected ranges but no patched release.","how_to_check":"- Run `SELECT VERSION();` on the MySQL server and compare against the affected ranges: MySQL Server 8.4.0 to 8.4.12, 9.7.0 to 9.7.3, 26.7.0 to 26.7.1; MySQL Cluster 8.0.0 to 8.0.49, 8.4.0 to 8.4.12, 9.7.0 to 9.7.3, 26.7.0 to 26.7.1.","needs_analyst":true,"not_affected_if":["auth-required","version-outside-range"],"who_is_affected":"Teams running MySQL Server or MySQL Cluster in the affected version ranges. The attacker needs high privileges, so databases where only tightly controlled administrative accounts can connect are at lower risk. Installations on versions outside the listed ranges are not affected.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000651,"input_tokens":3585,"output_tokens":586,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-101731':14A,17A '-2026':13A,16A '/av':158C '26.7.0':90C,101C '26.7.1':91C,102C '3.1':148C,157C '4.9':151C '8.0.0':94C '8.0.49':95C '8.4.0':86C,96C '8.4.12':87C,97C '9.7.0':88C,98C '9.7.3':89C,99C 'abil':131C 'access':39B,112C 'affect':82C 'allow':106C 'attack':109C,123C 'avail':152C 'base':149C 'caus':133C 'cluster':48B,70C,93C,121C,146C 'code':59B 'complet':140C 'compon':75C 'compromis':117C 'crash':9A,43B,139C 'cve':12A,15A 'cvss':147C,154C,156C 'data':62B 'databas':11A,18B 'denial':54B 'describ':51B 'dos':141C 'easili':103C 'execut':60B 'exploit':104C 'flaw':4A,25B 'frequent':137C 'h':166C 'h/ui':161C 'hang':40B,135C 'high':34B,107C 'high-privileg':33B 'host':23B 'impact':153C 'l/pr':160C 'let':5A,31B 'multipl':114C 'mysql':1A,19B,28B,44B,47B,67C,69C,74C,84C,92C,118C,120C,143C,145C 'n/a':165C 'n/ac':159C 'n/i':164C 'n/s':162C 'network':38B,111C 'optim':3A,30B,77C 'oracl':73C 'packag':20B 'privileg':7A,35B,108C 'product':71C 'protocol':115C 'repeat':42B,138C 'result':128C 'score':150C 'self':22B 'self-host':21B 'server':2A,29B,45B,68C,76C,85C,119C,144C 'servic':56B 'sourc':50B 'success':122C 'support':78C 'theft':63B 'u/c':163C 'unauthor':130C 'user':8A,36B 'vector':155C 'version':79C 'via':113C 'vulner':64C,105C,126C","nicknames":[],"mitigations":[],"who_affected":"Teams running MySQL Server or MySQL Cluster in the affected version ranges. The attacker needs high privileges, so databases where only tightly controlled administrative accounts can connect are at lower risk. Installations on versions outside the listed ranges are not affected.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T22:18:27+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-2026-101731","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-101731","severity":null,"published_at":"2026-10-20T22:18:27+00:00","modified_at":"2026-10-22T18:17:17+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"}