{"id":"CVE-2026-50259","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-50259","generatedAt":"2026-10-28T02:19:32.408Z","title":"A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256] indexed by key type index.","description":"A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256] indexed by key type index. The helper function CheckKeyTypes() writes to this buffer at a client-controlled offset, allowing a stack buffer overflow. This may be used to crash the server, or for privilege escalation if the X server runs as root.","published":"2026-06-05T12:16:39.000Z","lastModified":"2026-08-05T13:23:32.000Z","status":"Modified","sourceIdentifier":"secalert@redhat.com","cvss":{"version":"3.1","score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-121"],"affected":["x.org/x server","x.org/xwayland","redhat/enterprise linux"],"epss":{"score":0.00165,"percentile":0.05627,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://access.redhat.com/errata/RHSA-2026:26562","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:26566","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:26590","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:26610","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:26709","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:28923","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:29844","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:36083","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:36085","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:36086","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:36087","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:36632","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:36633","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:36634","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:36768","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:36791","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:36792","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:36798","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:38502","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:38810","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:46377","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:46382","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:46385","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:46392","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:46456","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:46460","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:46473","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:49519","source":"secalert@redhat.com"},{"url":"https://access.redhat.com/security/cve/CVE-2026-50259","tags":["Third 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BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}