{"id":"CVE-2026-101781","title":"mysql: mysql: Server takeover via Group Replication GCS (CVE-2026-101781)","summary":"A flaw was found in MySQL's Group Replication Group Communication System (GCS). An unauthenticated attacker located on the same adjacent network segment can exploit this vulnerability without requiring privileges or user interaction. Succe…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"vendor","cwe":"CWE-306","vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","affected":["enterprise_linux 10","enterprise_linux 9"],"published":"2026-10-20","updated":"2026-10-22","sourceUpdated":"2026-10-22T22:10:04+00:00","source":"CSAF","sourceUrl":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-101781.json","references":[{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-101781.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-101781"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2557856"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-101781"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-101781"},{"url":"https://www.oracle.com/security-alerts/cpuoct2026.html"}],"tags":["csaf","vex","red-hat","cve.org"],"epss":0.00279,"epssPercentile":0.20202,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-22T15:12:25.121261Z"},"ingestedAt":"2026-10-20T22:23:33.922Z","slug":"CVE-2026-101781","body":"## Overview\n\nA flaw was found in MySQL's Group Replication Group Communication System (GCS). An unauthenticated attacker located on the same adjacent network segment can exploit this vulnerability without requiring privileges or user interaction. Successful exploitation allows the attacker to take over the MySQL server, leading to unauthorized data disclosure, data modification, and denial of service.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-10-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-101781.json)\n\n**mysql: mysql: Server takeover via Group Replication GCS** — rated Important by Red Hat. Released 2026-10-20, updated 2026-10-22.\n\nAffected:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 9\n\nNo fix planned:\n\n- Red Hat Enterprise Linux 10\n- Red Hat Enterprise Linux 9\n\nNot affected:\n\n- Red Hat Enterprise Linux 6\n- Red Hat Hardened Images\n\n## Remediation\n\nAffected\n\nWorkarounds / mitigations:\n\n- Restrict network exposure by limiting communication on the Group Replication port to authorized cluster nodes using firewalld, or disable the Group Replication feature if it is not required.\n\n1. Restrict the replication communication port (default TCP 33061) to trusted cluster peer IPs using firewalld:\n# firewall-cmd --permanent --add-rich-rule='rule family=\"ipv4\" source address=\"<PEER_NODE_IP>\" port port=\"33061\" protocol=\"tcp\" accept'\n# firewall-cmd --reload\n\n2. Alternatively, if Group Replica…","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}