{"id":"CVE-2026-79680","title":"Authentication bypass vulnerability in the password authentication mechanism of the Qt VNC Server module","summary":"Authentication bypass vulnerability in the password authentication mechanism of the Qt VNC Server module. An attacker using a specially modified VNC client that violates the RFB protocol can bypass Qt VNC Server's password authentication…","severity":"medium","cvss":4.5,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/V:D/RE:L","cwe":["CWE-288","CWE-358"],"vendor":"qt","product":"qt","affected":["qt >= 6.4.0 < 6.8.9","qt >= 6.9.0 < 6.11.3"],"published":"2026-09-24","updated":"2026-09-24","sourceUpdated":"2026-09-24T21:08:22.573","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-79680","references":[{"url":"https://codereview.qt-project.org/c/qt/tqtc-qtvncserver/+/759160","label":"a59d8014-47c4-4630-ab43-e1b13cbe58e3"},{"url":"https://wiki.qt.io/List_of_known_vulnerabilities_in_Qt_products#CVE-2026-79680:","label":"a59d8014-47c4-4630-ab43-e1b13cbe58e3"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-79680.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-79680"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2540010"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-79680"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-79680"}],"tags":["nvd","cve.org","csaf","vex","red-hat","score-dispute"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-24T12:17:35.115651Z"},"cvssSource":"cna","ingestedAt":"2026-09-24T11:42:06.844Z","scores":{"cna":4.5,"vendor":6.8},"epss":0.00342,"epssPercentile":0.27601,"slug":"CVE-2026-79680","body":"## Overview\n\nAuthentication bypass vulnerability in the password authentication mechanism of the Qt VNC Server module. An attacker using a specially modified VNC client that violates the RFB protocol can bypass Qt VNC Server's password authentication and gain unauthorized remote access to the shared application, compromising the confidentiality and integrity of the session.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Hardened Images · no fix planned: Red Hat Hardened Images · updated 2026-09-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-79680.json)","depth":"sunlit","depthScore":25,"depthScoreParts":{"impact":24.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}