{"id":"CVE-2026-93518","kind":"vulnerability","aliases":["CVE-2026-93518"],"related":[],"title":"X.org X server: integer truncation lets authenticated clients overflow heap","description":"An integer truncation issue in XkbResizeKeyType() that could lead to a heap buffer overflow by authenticated X clients in X.org X server before 21.1.25 and XWayland before 24.1.14 could be exploited for crashes or potential code execution in the X server.","summary":"An integer truncation bug in XkbResizeKeyType() lets an authenticated X client trigger a heap buffer overflow in the X.org X server or XWayland. An attacker can crash the server or potentially run code inside it.","severity":"high","cvss":7.8,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["bsd-desktop","infrastructure","linux-desktop","x.org","xwayland"],"not_affected_if":["no-x-server","wayland-only"],"how_to_check":"- Run `Xorg -version` or `X -version` and compare against `21.1.25`\n- Run `Xwayland -version` and compare against `24.1.14`\n- Check your distribution's package manager for the installed xorg-server or xwayland version","fix":"- Upgrade xorg-server to `21.1.25` or later\n- Upgrade XWayland to `24.1.14` or later\n- Install the distribution's xorg-server or xwayland security update when available","status":"open","published_at":"2026-10-28T15:17:10+00:00","first_seen_at":"2026-10-28T15:33:37+00:00","triaged_at":"2026-10-28T15:35:05+00:00","updated_at":"2026-10-28T15:35:05+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-28T15:35:05Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade xorg-server to `21.1.25` or later\n- Upgrade XWayland to `24.1.14` or later\n- Install the distribution's xorg-server or xwayland security update when available","reach":"local","title":"X.org X server: integer truncation lets authenticated clients overflow heap","impact":"high","summary":"An integer truncation bug in XkbResizeKeyType() lets an authenticated X client trigger a heap buffer overflow in the X.org X server or XWayland. An attacker can crash the server or potentially run code inside it.","category":"infrastructure","nicknames":[],"who_cares":["x.org","xwayland","linux-desktop","bsd-desktop"],"confidence":0.6,"needs_auth":"yes","worst_case":"Authenticated X client crashes server or may execute code","analyst_note":"Sources give only the NVD entry; confirm the fixed package versions and whether a distribution advisory lists backports, at https://nvd.nist.gov/vuln/detail/CVE-2026-93518.","how_to_check":"- Run `Xorg -version` or `X -version` and compare against `21.1.25`\n- Run `Xwayland -version` and compare against `24.1.14`\n- Check your distribution's package manager for the installed xorg-server or xwayland version","needs_analyst":true,"not_affected_if":["no-x-server","wayland-only"],"who_is_affected":"Systems running an X.org X server before 21.1.25 or XWayland before 24.1.14, including Linux and BSD desktops and any host where an X server is exposed to users. Only clients that can already connect to the X server can trigger the flaw, so single-user machines with no untrusted X clients face less risk. Headless servers without an X server can skip it.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"high"},"cost_usd":0.000648,"input_tokens":3309,"output_tokens":634,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2026':12A,15A '-93518':13A,16A '21.1.25':83C '24.1.14':87C 'attack':50B 'authent':7A,34B,75C 'bsd':18B 'bsd-desktop':17B 'buffer':40B,72C 'bug':29B 'client':8A,36B,77C 'code':58B,95C 'could':67C,88C 'crash':52B,92C 'cve':11A,14A 'desktop':19B,23B 'execut':96C 'exploit':90C 'heap':10A,39B,71C 'infrastructur':20B 'insid':59B 'integ':4A,27B,61C 'issu':63C 'lead':68C 'let':6A,32B 'linux':22B 'linux-desktop':21B 'overflow':9A,41B,73C 'potenti':56B,94C 'run':57B 'server':3A,46B,54B,81C,100C 'trigger':37B 'truncat':5A,28B,62C 'x':2A,35B,45B,76C,80C,99C 'x.org':1A,24B,44B,79C 'xkbresizekeytyp':31B,65C 'xwayland':25B,48B,85C","nicknames":[],"mitigations":[],"who_affected":"Systems running an X.org X server before 21.1.25 or XWayland before 24.1.14, including Linux and BSD desktops and any host where an X server is exposed to users. Only clients that can already connect to the X server can trigger the flaw, so single-user machines with no untrusted X clients face less risk. Headless servers without an X server can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-28T15:17:10+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvss_by":"meissner@suse.de","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-93518","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93518","severity":null,"published_at":"2026-10-28T15:17:10+00:00","modified_at":"2026-10-28T15:21:55+00:00","first_seen_at":"2026-10-28T15:33:37+00:00","fetched_at":"2026-10-28T15:33:37+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"}