CVE-2026-34003

/* * PoC for CVE-2026-34003: X.Org X Server XKB Key Types OOB * This is a conceptual proof of concept. * Compile with: gcc -o poc_xkb poc_xkb.c -lX11 */ #include <X11/Xlib.h> #include <X11/XKBlib.h> #include <stdio.h> #include <stdlib.h> int main() { Display *dpy; // Attempt to connect to the X server dpy = XOpenDisplay(NULL); if (!dpy) { fprintf(stderr, "Cannot open display\n"); return 1; } printf("Connected to X Server. Sending malformed XKB request...\n"); // Note: Actual exploitation requires crafting a specific XKB protocol request // that triggers the out-of-bounds access. This usually involves manipulating // the length fields in the XKBGetTypeInfo or similar requests. // In a real exploit scenario, one would use a custom buffer: // char buffer[1024]; // memset(buffer, 0x41, sizeof(buffer)); // Fill with 'A' // Send request via XSendEvent or direct protocol manipulation... // For demonstration, we just check XKB extension presence int major, minor, opcode, event, error; if (XkbQueryExtension(dpy, &opcode, &event, &error, &major, &minor)) { printf("XKB extension found. Version: %d.%d\n", major, minor); printf("Vulnerability CVE-2026-34003 may be exploitable.\n"); } else { printf("XKB extension not found.\n"); } XCloseDisplay(dpy); return 0; }

{"cve": {"id": "CVE-2026-34003", "sourceIdentifier": "[email protected]", "published": "2026-04-23T16:16:24.920", "lastModified": "2026-05-20T04:16:53.177", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "A flaw was found in the X.Org X server's XKB key types request validation. A local attacker could send a specially crafted request to the X server, leading to an out-of-bounds memory access vulnerability. This could result in the disclosure of sensitive information or cause the server to crash, leading to a Denial of Service (DoS). In certain configurations, higher impact outcomes may be possible."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-125"}]}], "references": [{"url": "https://access.redhat.com/errata/RHSA-2026:10739", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:11352", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:11369", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:11388", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:11656", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:11692", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:13414", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:19125", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:19342", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:19343", "source": "[email protected]"}, {"url": "https://access.redhat.com/errata/RHSA-2026:19344", "source": "[email protected]"}, {"url": "https://access.redhat.com/security/cve/CVE-2026-34003", "source": "[email protected]"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2451113", "source": "[email protected]"}]}}