{"id":"CVE-2026-101799","kind":"vulnerability","aliases":["CVE-2026-101799"],"related":[],"title":"MySQL Server: Group Replication flaw lets an adjacent attacker crash the server","description":"Vulnerability in the MySQL Server, MySQL Cluster product of Oracle MySQL (component: Server: Group Replication GCS).  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 unauthenticated attacker with access to the physical communication segment attached to the hardware where the MySQL Server, MySQL Cluster executes 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 6.5 (Availability impacts).  CVSS Vector: (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).","summary":"A flaw in the Group Replication GCS component of MySQL Server and MySQL Cluster lets an unauthenticated attacker on the same network segment hang or repeatedly crash the server. The impact is denial of service only, with no data read or code execution stated.","severity":"medium","cvss":6.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["database","group-replication","mysql","package","self-hosted"],"not_affected_if":["isolated-network","standalone-server"],"how_to_check":"- Run `SELECT @@version;` in the MySQL client and compare against the affected ranges: 8.0.0-8.0.49, 8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1.\n- Check whether Group Replication is in use with `SELECT * FROM performance_schema.replication_group_members;`","fix":"- Upgrade MySQL Server 8.4.x to a release after `8.4.12`, 9.7.x to a release after `9.7.3`, or 26.7.x to a release after `26.7.1`.\n- Upgrade MySQL Cluster 8.0.x to a release after `8.0.49`.\n- Oracle's patch version numbers are unknown from the sources.","status":"open","published_at":"2026-10-20T22:18:35+00:00","first_seen_at":"2026-10-23T21:57:23+00:00","triaged_at":"2026-10-25T03:53:40+00:00","updated_at":"2026-10-25T03:53:40+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-25T03:53:40Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade MySQL Server 8.4.x to a release after `8.4.12`, 9.7.x to a release after `9.7.3`, or 26.7.x to a release after `26.7.1`.\n- Upgrade MySQL Cluster 8.0.x to a release after `8.0.49`.\n- Oracle's patch version numbers are unknown from the sources.","reach":"network","title":"MySQL Server: Group Replication flaw lets an adjacent attacker crash the server","impact":"low","summary":"A flaw in the Group Replication GCS component of MySQL Server and MySQL Cluster lets an unauthenticated attacker on the same network segment hang or repeatedly crash the server. The impact is denial of service only, with no data read or code execution stated.","category":"package","nicknames":[],"who_cares":["mysql","self-hosted","database","group-replication"],"confidence":0.6,"needs_auth":"no","worst_case":"Server hangs or repeatedly crashes, causing a complete denial of service.","analyst_note":"Confirm the exact Oracle patch versions and whether Group Replication is required for exposure; check the Oracle Critical Patch Update advisory for fixed builds.","how_to_check":"- Run `SELECT @@version;` in the MySQL client and compare against the affected ranges: 8.0.0-8.0.49, 8.4.0-8.4.12, 9.7.0-9.7.3, 26.7.0-26.7.1.\n- Check whether Group Replication is in use with `SELECT * FROM performance_schema.replication_group_members;`","needs_analyst":true,"not_affected_if":["standalone-server","isolated-network"],"who_is_affected":"Teams running MySQL Server or MySQL Cluster on the affected versions with Group Replication, where the GCS traffic travels over a network segment an attacker can reach. The sources describe an attacker with access to the physical communication segment, so hosts on isolated networks with no shared segment are lower risk. Standalone servers without Group Replication are not clearly in scope.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000731,"input_tokens":3619,"output_tokens":739,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-101799':15A,18A '-2026':14A,17A '/av':179C '26.7.0':100C,111C '26.7.1':101C,112C '3.1':169C,178C '6.5':172C '8.0.0':104C '8.0.49':105C '8.4.0':96C,106C '8.4.12':97C,107C '9.7.0':98C,108C '9.7.3':99C,109C 'a/ac':180C 'abil':152C 'access':120C 'adjac':8A 'affect':92C 'allow':116C 'attach':126C 'attack':9A,45B,118C,144C 'avail':173C 'base':170C 'caus':154C 'cluster':41B,78C,103C,135C,142C,167C 'code':69B 'communic':124C 'complet':161C 'compon':35B,83C 'compromis':138C 'crash':10A,54B,160C 'cve':13A,16A 'cvss':168C,175C,177C 'data':66B 'databas':19B 'denial':60B 'dos':162C 'easili':113C 'execut':70B,136C 'exploit':114C 'flaw':5A,29B 'frequent':158C 'gcs':34B,87C 'group':3A,21B,32B,85C 'group-repl':20B 'h':187C 'hang':51B,156C 'hardwar':129C 'host':27B 'impact':58B,174C 'l/pr':181C 'let':6A,42B 'mysql':1A,23B,37B,40B,75C,77C,82C,94C,102C,132C,134C,139C,141C,164C,166C 'n/a':186C 'n/i':185C 'n/s':183C 'n/ui':182C 'network':49B 'oracl':81C 'packag':24B 'physic':123C 'product':79C 'read':67B 'repeat':53B,159C 'replic':4A,22B,33B,86C 'result':149C 'score':171C 'segment':50B,125C 'self':26B 'self-host':25B 'server':2A,12A,38B,56B,76C,84C,95C,133C,140C,165C 'servic':62B 'state':71B 'success':143C 'support':88C 'u/c':184C 'unauthent':44B,117C 'unauthor':151C 'vector':176C 'version':89C 'vulner':72C,115C,147C","nicknames":[],"mitigations":[],"who_affected":"Teams running MySQL Server or MySQL Cluster on the affected versions with Group Replication, where the GCS traffic travels over a network segment an attacker can reach. The sources describe an attacker with access to the physical communication segment, so hosts on isolated networks with no shared segment are lower risk. Standalone servers without Group Replication are not clearly in scope.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-20T22:18:35+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:A/AC:L/PR:N/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-2026-101799","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-101799","severity":null,"published_at":"2026-10-20T22:18:35+00:00","modified_at":"2026-10-22T18:17:24+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"}