{"id":"CVE-2026-109089","kind":"vulnerability","aliases":["CVE-2026-109089"],"related":[],"title":"libXi: heap buffer overflow in DEVICE_RESOLUTION handling from malicious X server","description":"A buffer overflow when handling DEVICE_RESOLUTION in libXi before 1.8.4 could overflow a heap, triggered by a malicious X server.","summary":"libXi versions before 1.8.4 contain a buffer overflow when parsing DEVICE_RESOLUTION replies, which can overflow a heap buffer. A malicious X server can trigger it, which may let an attacker corrupt memory in the client program.","severity":"high","cvss":7.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["desktop","infrastructure","libxi","linux","x11"],"not_affected_if":["no-x11-clients","wayland-only"],"how_to_check":"- `xdpyinfo` or `pkg-config --modversion xi` to find the installed libXi version\n- Check the installed libXi package with your OS package manager, for example `dpkg -l libxi6` or `rpm -q libXi`","fix":"- Upgrade libXi to `1.8.4` or later through your OS package manager\n- Rebuild dependent applications that link statically against libXi","status":"open","published_at":"2026-10-27T17:16:57+00:00","first_seen_at":"2026-10-27T17:32:45+00:00","triaged_at":"2026-10-27T17:34:39+00:00","updated_at":"2026-10-27T17:34:39+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-10-27T17:34:39Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade libXi to `1.8.4` or later through your OS package manager\n- Rebuild dependent applications that link statically against libXi","reach":"unknown","title":"libXi: heap buffer overflow in DEVICE_RESOLUTION handling from malicious X server","impact":"high","summary":"libXi versions before 1.8.4 contain a buffer overflow when parsing DEVICE_RESOLUTION replies, which can overflow a heap buffer. A malicious X server can trigger it, which may let an attacker corrupt memory in the client program.","category":"infrastructure","nicknames":[],"who_cares":["linux","x11","libxi","desktop"],"confidence":0.5,"needs_auth":"unknown","worst_case":"Heap memory corruption in a client program, possibly leading to code execution","analyst_note":"Confirm the affected version range and whether the malicious server is the only trigger; check the NVD entry and the upstream libXi advisory for details.","how_to_check":"- `xdpyinfo` or `pkg-config --modversion xi` to find the installed libXi version\n- Check the installed libXi package with your OS package manager, for example `dpkg -l libxi6` or `rpm -q libXi`","needs_analyst":true,"not_affected_if":["wayland-only","no-x11-clients"],"who_is_affected":"Programs that use libXi to talk to an X server, such as desktop sessions and X11 clients on Linux and BSD systems. Exposure depends on connecting to an X server the attacker controls, so machines that only use Wayland or never open X connections to untrusted servers are less likely to be at risk. unknown whether the sources list specific affected distributions.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000636,"input_tokens":3282,"output_tokens":615,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-109089':15A,18A '-2026':14A,17A '1.8.4':27B,71C 'attack':54B 'buffer':3A,30B,42B,62C 'client':59B 'contain':28B 'corrupt':55B 'could':72C 'cve':13A,16A 'desktop':19B 'devic':6A,34B,66C 'handl':8A,65C 'heap':2A,41B,75C 'infrastructur':20B 'let':52B 'libxi':1A,21B,24B,69C 'linux':22B 'malici':10A,44B,79C 'may':51B 'memori':56B 'overflow':4A,31B,39B,63C,73C 'pars':33B 'program':60B 'repli':36B 'resolut':7A,35B,67C 'server':12A,46B,81C 'trigger':48B,76C 'version':25B 'x':11A,45B,80C 'x11':23B","nicknames":[],"mitigations":[],"who_affected":"Programs that use libXi to talk to an X server, such as desktop sessions and X11 clients on Linux and BSD systems. Exposure depends on connecting to an X server the attacker controls, so machines that only use Wayland or never open X connections to untrusted servers are less likely to be at risk. unknown whether the sources list specific affected distributions.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-27T17:16:57+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","cvss_by":"meissner@suse.de","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-109089","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-109089","severity":null,"published_at":"2026-10-27T17:16:57+00:00","modified_at":"2026-10-27T17:16:57+00:00","first_seen_at":"2026-10-27T17:32:45+00:00","fetched_at":"2026-10-27T17:32:45+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"}