{"id":"CVE-2026-128885","kind":"vulnerability","aliases":["CVE-2026-128885"],"related":[],"title":"D-Bus: fd overflow in select() fallback lets local users crash daemon","description":"A flaw was found in D-Bus. In configurations where the daemon falls back to using the Unix select() mechanism for event monitoring, it does not verify whether file descriptor numbers exceed allocated limits. A local attacker can exploit this flaw by opening a large number of concurrent connections to trigger an out-of-bounds write on the stack. This can cause the daemon to crash, resulting in a Denial of Service (DoS).","summary":"In D-Bus builds that fall back to the Unix select() event loop, the daemon does not check whether file descriptor numbers exceed the allocated limit. A local attacker who opens many concurrent connections can trigger an out-of-bounds stack write that crashes the daemon.","severity":"medium","cvss":5.5,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["dbus","infrastructure","linux","local-users"],"not_affected_if":["default-config","no-local-untrusted-users"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-13T21:17:45+00:00","first_seen_at":"2026-11-13T21:33:41+00:00","triaged_at":"2026-11-13T21:33:51+00:00","updated_at":"2026-11-13T21:33:51+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-11-13T21:33:51Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"D-Bus: fd overflow in select() fallback lets local users crash daemon","impact":"low","summary":"In D-Bus builds that fall back to the Unix select() event loop, the daemon does not check whether file descriptor numbers exceed the allocated limit. A local attacker who opens many concurrent connections can trigger an out-of-bounds stack write that crashes the daemon.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["dbus","linux","local-users"],"confidence":0.6,"fix_status":"unknown","needs_auth":"unknown","worst_case":"local attacker crashes the D-Bus daemon, denial of service","analyst_note":"Check the NVD entry and the D-Bus upstream advisory for the affected versions, fixed release, and whether the select() fallback is a default build option.","how_to_check":"- unknown","plain_action":"","product_name":"dbus","needs_analyst":true,"not_affected_if":["default-config","no-local-untrusted-users"],"who_is_affected":"Only systems where the D-Bus daemon is configured to use the select() fallback for event monitoring are described as exposed; the sources do not say which default or distributions do this. Local users who can open connections to the bus are the attackers described. Systems using the default poll-based event loop are not stated to be affected.","user_interaction":"no","product_ecosystem":"vendor","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000716,"input_tokens":4568,"output_tokens":519,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-128885':16A,19A '-2026':15A,18A 'alloc':51B,107C 'attack':55B,111C 'back':33B,88C 'bound':67B,130C 'build':30B 'bus':3A,29B,81C 'caus':137C 'check':44B 'concurr':59B,122C 'configur':83C 'connect':60B,123C 'crash':12A,71B,141C 'cve':14A,17A 'd':2A,28B,80C 'd-bus':1A,27B,79C 'daemon':13A,41B,73B,86C,139C 'dbus':20B 'denial':145C 'descriptor':47B,104C 'dos':148C 'event':38B,96C 'exceed':49B,106C 'exploit':113C 'fall':32B,87C 'fallback':8A 'fd':4A 'file':46B,103C 'flaw':75C,115C 'found':77C 'infrastructur':21B 'larg':119C 'let':9A 'limit':52B,108C 'linux':22B 'local':10A,24B,54B,110C 'local-us':23B 'loop':39B 'mani':58B 'mechan':94C 'monitor':97C 'number':48B,105C,120C 'open':57B,117C 'out-of-bound':64B,127C 'overflow':5A 'result':142C 'select':7A,37B,93C 'servic':147C 'stack':68B,134C 'trigger':62B,125C 'unix':36B,92C 'use':90C 'user':11A,25B 'verifi':101C 'whether':45B,102C 'write':69B,131C","nicknames":[],"mitigations":[],"who_affected":"Only systems where the D-Bus daemon is configured to use the select() fallback for event monitoring are described as exposed; the sources do not say which default or distributions do this. Local users who can open connections to the bus are the attackers described. Systems using the default poll-based event loop are not stated to be affected.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["dbus","infrastructure","linux","localusers","medium"],"campaign_type":null,"search_a":"'-128885':16A,19A '-2026':15A,18A 'bus':3A 'crash':12A 'cve':14A,17A 'd':2A 'd-bus':1A 'daemon':13A 'fallback':8A 'fd':4A 'let':9A 'local':10A 'overflow':5A 'select':7A 'user':11A","search_b":"'alloc':51B 'attack':55B 'back':33B 'bound':67B 'build':30B 'bus':29B 'check':44B 'concurr':59B 'connect':60B 'crash':71B 'd':28B 'd-bus':27B 'daemon':41B,73B 'dbus':20B 'descriptor':47B 'event':38B 'exceed':49B 'fall':32B 'file':46B 'infrastructur':21B 'limit':52B 'linux':22B 'local':24B,54B 'local-us':23B 'loop':39B 'mani':58B 'number':48B 'open':57B 'out-of-bound':64B 'select':37B 'stack':68B 'trigger':62B 'unix':36B 'user':25B 'whether':45B 'write':69B","search_c":"'alloc':107C 'attack':111C 'back':88C 'bound':130C 'bus':81C 'caus':137C 'concurr':122C 'configur':83C 'connect':123C 'crash':141C 'd':80C 'd-bus':79C 'daemon':86C,139C 'denial':145C 'descriptor':104C 'dos':148C 'event':96C 'exceed':106C 'exploit':113C 'fall':87C 'file':103C 'flaw':75C,115C 'found':77C 'larg':119C 'limit':108C 'local':110C 'mechan':94C 'monitor':97C 'number':105C,120C 'open':117C 'out-of-bound':127C 'result':142C 'select':93C 'servic':147C 'stack':134C 'trigger':125C 'unix':92C 'use':90C 'verifi':101C 'whether':102C 'write':131C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-13T21:17:45+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvss_by":"secalert@redhat.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-128885","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-128885","severity":null,"published_at":"2026-11-13T21:17:45+00:00","modified_at":"2026-11-13T21:17:45+00:00","first_seen_at":"2026-11-13T21:33:41+00:00","fetched_at":"2026-11-13T21:33:41+00:00","note":null}],"documents":[],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}