{"id":"CVE-2026-98953","kind":"vulnerability","aliases":["CVE-2026-98953"],"related":[],"title":"Linux kernel: devlink reference leak when nested notify work is pending","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndevlink: fix devlink_rel reference leak when notify work is pending\n\ndevlink_rel_nested_in_notify_work_schedule() takes a reference on the\ndevlink_rel for the notify work and then queues the work, ignoring the\nreturn value of schedule_delayed_work(). If the work is already pending,\nnothing new is queued, the work runs only once and drops only one\nreference, so the extra one is leaked together with the devlink_rel and\nits index in devlink_rels.\n\nThis is easy to hit. devl_register() of a nested instance queues the\nwork, and if the instance is unregistered before the work has run,\ndevlink_rel_put() queues it again while it is still pending. The work\nalso keeps rescheduling itself for as long as the parent devlink lock\ncannot be taken, which widens the window. Registering and unregistering\na nested devlink instance 100 times while holding the parent lock leaks\nall 100 devlink_rel objects.\n\nThe reschedule path in devlink_rel_nested_in_notify_work() has the same\nproblem: if the work was queued again while it was running, the\nreference it holds is never dropped.\n\nDrop the reference in both places when the work was already pending.\nThe pending work holds its own reference, so this can not be the last\none.","summary":"In the Linux kernel's devlink subsystem, a reference taken for queued notify work is leaked when the work is already pending, so each register and unregister cycle of a nested devlink instance leaks a devlink_rel object and its index. The sources describe a resource leak; they do not state a code execution or privilege escalation path.","severity":"unknown","cvss":null,"epss":0.00209,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["devlink","linux-kernel","network-hardware","runtime"],"not_affected_if":["no-devlink-usage"],"how_to_check":"- `uname -r` and compare against the fixed kernel builds listed in the NVD entry\n- unknown whether the sources list affected kernel version ranges","fix":"- Update the Linux kernel to a build that includes the upstream devlink fix (fixed version: unknown)\n- unknown whether distribution kernel packages have shipped the fix","status":"open","published_at":"2026-10-23T13:17:16+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","triaged_at":"2026-10-25T04:57:52+00:00","updated_at":"2026-10-25T12:38:50+00:00","category":"runtime","confidence":0.5,"triage":{"at":"2026-10-25T04:57:52Z","model":"claude-haiku-5-5","output":{"fix":"- Update the Linux kernel to a build that includes the upstream devlink fix (fixed version: unknown)\n- unknown whether distribution kernel packages have shipped the fix","reach":"local","title":"Linux kernel: devlink reference leak when nested notify work is pending","impact":"low","summary":"In the Linux kernel's devlink subsystem, a reference taken for queued notify work is leaked when the work is already pending, so each register and unregister cycle of a nested devlink instance leaks a devlink_rel object and its index. The sources describe a resource leak; they do not state a code execution or privilege escalation path.","category":"runtime","nicknames":[],"who_cares":["linux-kernel","devlink","network-hardware"],"confidence":0.5,"needs_auth":"unknown","worst_case":"unknown; reference leak exhausts kernel devlink resources","analyst_note":"Confirm affected and fixed kernel version ranges from the NVD entry or the kernel stable commit; the sources give no version data.","how_to_check":"- `uname -r` and compare against the fixed kernel builds listed in the NVD entry\n- unknown whether the sources list affected kernel version ranges","needs_analyst":true,"not_affected_if":["no-devlink-usage"],"who_is_affected":"Systems running a Linux kernel with devlink support and nested devlink instances, typically hosts with managed network hardware or devlink-capable NICs that create and destroy nested instances. Systems without devlink use or nested instances are unlikely to be exercised by this leak. The sources do not state the exact exposure.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000654,"input_tokens":3634,"output_tokens":581,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-98953':14A,17A '100':237C,246C 'alreadi':46B,140C,291C 'also':211C 'cannot':223C 'code':78B 'cve':12A,15A 'cycl':53B 'delay':134C 'describ':69B 'devl':178C 'devlink':3A,18B,31B,57B,61B,94C,96C,105C,117C,165C,171C,198C,221C,235C,247C,254C 'drop':152C,280C,281C 'easi':175C 'escal':82B 'execut':79B 'extra':158C 'fix':95C 'follow':89C 'hardwar':24B 'hit':177C 'hold':240C,277C,296C 'ignor':128C 'index':66B,169C 'instanc':58B,183C,190C,236C 'keep':212C 'kernel':2A,21B,29B,87C 'last':306C 'leak':5A,41B,59B,72B,99C,161C,244C 'linux':1A,20B,28B,86C 'linux-kernel':19B 'lock':222C,243C 'long':217C 'nest':7A,56B,107C,182C,234C,256C 'network':23B 'network-hardwar':22B 'never':279C 'new':143C 'noth':142C 'notifi':8A,38B,101C,109C,121C,258C 'object':63B,249C 'one':154C,159C,307C 'parent':220C,242C 'path':83B,252C 'pend':11A,47B,104C,141C,208C,292C,294C 'place':286C 'privileg':81B 'problem':263C 'put':200C 'queu':37B,145C,268C 'queue':125C,184C,201C 'refer':4A,34B,98C,114C,155C,275C,283C,299C 'regist':50B,179C,230C 'rel':62B,97C,106C,118C,166C,172C,199C,248C,255C 'reschedul':213C,251C 'resolv':93C 'resourc':71B 'return':130C 'run':148C,197C,273C 'runtim':25B 'schedul':111C,133C 'sourc':68B 'state':76B 'still':207C 'subsystem':32B 'take':112C 'taken':35B,225C 'time':238C 'togeth':162C 'unregist':52B,192C,232C 'valu':131C 'vulner':90C 'widen':227C 'window':229C 'work':9A,39B,44B,102C,110C,122C,127C,135C,138C,147C,186C,195C,210C,259C,266C,289C,295C","nicknames":[],"mitigations":[],"who_affected":"Systems running a Linux kernel with devlink support and nested devlink instances, typically hosts with managed network hardware or devlink-capable NICs that create and destroy nested instances. Systems without devlink use or nested instances are unlikely to be exercised by this leak. The sources do not state the exact exposure.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-23T13:17:16+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98953","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98953","severity":null,"published_at":"2026-10-23T13:17:16+00:00","modified_at":"2026-10-23T13:17:16+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","fetched_at":"2026-10-23T22:29:03+00:00","note":null},{"source":"epss","external_id":"CVE-2026-98953","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98953","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-25T12:38:50+00:00","fetched_at":"2026-10-25T12:38:50+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"}