{"id":"CVE-2026-99267","kind":"vulnerability","aliases":["CVE-2026-99267"],"related":[],"title":"Linux kernel: io_uring NAPI entries never expire, keep being polled","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/napi: make stale entries time out after 60s\n\nWith dynamic tracking a NAPI id that hasn't been seen for a minute is\nmeant to be dropped from the list the ring busy polls. The timeout is\nadded to jiffies, but it is defined as 60 * SEC_CONVERSION, and\nSEC_CONVERSION isn't the number of jiffies in a second. It is the\ninternal factor of __timespec64_to_jiffies(), HZ scaled up by\nSEC_JIFFIE_SC bits. For HZ=1000 that is 1000 << 22, which puts the\ntimeout at about eight years. On 32-bit the multiplication overflows.\n\nSo entries are never removed, and every id that a socket of the ring\never had keeps being polled on each wait.","summary":"The Linux kernel's io_uring busy-poll tracking computes its 60-second timeout with the wrong unit, so stale NAPI IDs are never dropped. Every network ID a ring has ever used keeps being polled on each wait, which wastes CPU and can degrade the system.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["io_uring","linux-kernel","runtime","self-hosted"],"not_affected_if":["no-io-uring-napi"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-03T12:17:33+00:00","first_seen_at":"2026-11-03T12:20:40+00:00","triaged_at":"2026-11-03T12:22:38+00:00","updated_at":"2026-11-03T12:22:38+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-11-03T12:22:38Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Linux kernel: io_uring NAPI entries never expire, keep being polled","impact":"low","summary":"The Linux kernel's io_uring busy-poll tracking computes its 60-second timeout with the wrong unit, so stale NAPI IDs are never dropped. Every network ID a ring has ever used keeps being polled on each wait, which wastes CPU and can degrade the system.","audience":"businesses","category":"runtime","nicknames":[],"who_cares":["linux-kernel","io_uring","self-hosted"],"confidence":0.6,"fix_status":"unknown","needs_auth":"unknown","worst_case":"Wasted CPU on every wait; no code execution stated","analyst_note":"Check the kernel stable-tree commit and affected version ranges; the sources give no severity or fixed version.","how_to_check":"- unknown","plain_action":"","needs_analyst":true,"not_affected_if":["no-io-uring-napi"],"who_is_affected":"Systems running a Linux kernel that uses io_uring with NAPI busy polling enabled are affected; the sources do not say which kernel versions. Systems that do not use io_uring NAPI busy polling are likely not affected, but the sources do not confirm this.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000667,"input_tokens":4298,"output_tokens":474,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-99267':14A,17A '1000':165C,168C '22':169C '32':179C '60':39B,131C '60s':93C 'add':123C 'bit':162C,180C 'busi':34B,118C 'busy-pol':33B 'comput':37B 'convers':133C,136C 'cpu':69B 'cve':12A,15A 'defin':129C 'degrad':72B 'drop':52B,112C 'dynam':95C 'eight':176C 'entri':6A,89C,185C 'ever':59B,198C 'everi':53B,190C 'expir':8A 'factor':150C 'follow':80C 'hasn':101C 'host':26B 'hz':155C,164C 'id':49B,55B,99C,191C 'intern':149C 'io':3A,18B,31B,85C 'isn':137C 'jiffi':125C,142C,154C,160C 'keep':9A,61B,200C 'kernel':2A,22B,29B,78C 'linux':1A,21B,28B,77C 'linux-kernel':20B 'list':115C 'make':87C 'meant':109C 'minut':107C 'multipl':182C 'napi':5A,48B,98C 'network':54B 'never':7A,51B,187C 'number':140C 'overflow':183C 'poll':11A,35B,63B,119C,202C 'put':171C 'remov':188C 'resolv':84C 'ring':57B,117C,197C 'runtim':23B 'sc':161C 'scale':156C 'sec':132C,135C,159C 'second':40B,145C 'seen':104C 'self':25B 'self-host':24B 'socket':194C 'stale':47B,88C 'system':74B 'time':90C 'timeout':41B,121C,173C 'timespec64':152C 'track':36B,96C 'unit':45B 'ure':4A,19B,32B 'uring/napi':86C 'use':60B 'vulner':81C 'wait':66B,205C 'wast':68B 'wrong':44B 'year':177C","nicknames":[],"mitigations":[],"who_affected":"Systems running a Linux kernel that uses io_uring with NAPI busy polling enabled are affected; the sources do not say which kernel versions. Systems that do not use io_uring NAPI busy polling are likely not affected, but the sources do not confirm this.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"unknown","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["iouring","linuxkernel","runtime","selfhosted","unknown"],"first_public_at":"2026-11-03T12:17:33+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-99267","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99267","severity":null,"published_at":"2026-11-03T12:17:33+00:00","modified_at":"2026-11-03T12:17:33+00:00","first_seen_at":"2026-11-03T12:20:40+00:00","fetched_at":"2026-11-03T12:20:40+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"}