{"id":"CVE-2026-93520","kind":"vulnerability","aliases":["CVE-2026-93520"],"related":[],"title":"X.org X server: heap overflow lets authenticated clients run code","description":"A heap buffer overflow caused by mismatching size calculations between XkbAllocNames and  ChangeKeycodeRange in X.org X server before 2.1.25 and XWayland before 24.1.14 could be used by authenticated X clients to crash or potentially execute code in X server context.","summary":"A size mismatch between XkbAllocNames and ChangeKeycodeRange in the X.org X server and XWayland causes a heap buffer overflow. An authenticated X client can crash the server or potentially execute code in the X server context.","severity":"high","cvss":7.8,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","linux-desktop","self-hosted","x11","xwayland"],"not_affected_if":["no-x-server","wayland-only"],"how_to_check":"- `Xorg -version` or `Xwayland -version` to read the installed server version\n- unknown","fix":"- Upgrade the X.org X server to `2.1.25` or later\n- Upgrade XWayland to `24.1.14` or later","status":"open","published_at":"2026-10-28T15:17:10+00:00","first_seen_at":"2026-10-28T15:33:37+00:00","triaged_at":"2026-10-28T15:35:04+00:00","updated_at":"2026-10-28T15:35:04+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-28T15:35:04Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade the X.org X server to `2.1.25` or later\n- Upgrade XWayland to `24.1.14` or later","reach":"local","title":"X.org X server: heap overflow lets authenticated clients run code","impact":"high","summary":"A size mismatch between XkbAllocNames and ChangeKeycodeRange in the X.org X server and XWayland causes a heap buffer overflow. An authenticated X client can crash the server or potentially execute code in the X server context.","category":"infrastructure","nicknames":[],"who_cares":["x11","xwayland","linux-desktop","self-hosted"],"confidence":0.6,"needs_auth":"yes","worst_case":"Authenticated X client crashes the server or potentially executes code","analyst_note":"Confirm the exact affected X.org and XWayland version ranges and the package fix versions from the NVD entry or the upstream X.org advisory.","how_to_check":"- `Xorg -version` or `Xwayland -version` to read the installed server version\n- unknown","needs_analyst":true,"not_affected_if":["no-x-server","wayland-only"],"who_is_affected":"Systems running the X.org X server before `2.1.25` or XWayland before `24.1.14`. Exposure requires an authenticated X client that can reach the server; the sources do not say how commonly that is possible on desktops or multi-user hosts. Systems with no X server or XWayland installed can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000597,"input_tokens":3320,"output_tokens":530,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2026':12A,15A '-93520':13A,16A '2.1.25':80C '24.1.14':84C 'authent':7A,46B,89C 'buffer':43B,64C 'calcul':70C 'caus':40B,66C 'changekeycoderang':32B,74C 'client':8A,48B,91C 'code':10A,56B,97C 'context':61B,101C 'could':85C 'crash':50B,93C 'cve':11A,14A 'desktop':20B 'execut':55B,96C 'heap':4A,42B,63C 'host':23B 'infrastructur':17B 'let':6A 'linux':19B 'linux-desktop':18B 'mismatch':28B,68C 'overflow':5A,44B,65C 'potenti':54B,95C 'run':9A 'self':22B 'self-host':21B 'server':3A,37B,52B,60B,78C,100C 'size':27B,69C 'use':87C 'x':2A,36B,47B,59B,77C,90C,99C 'x.org':1A,35B,76C 'x11':24B 'xkballocnam':30B,72C 'xwayland':25B,39B,82C","nicknames":[],"mitigations":[],"who_affected":"Systems running the X.org X server before `2.1.25` or XWayland before `24.1.14`. Exposure requires an authenticated X client that can reach the server; the sources do not say how commonly that is possible on desktops or multi-user hosts. Systems with no X server or XWayland installed 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-2026-93520","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93520","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"}