{"id":"CVE-2026-98491","kind":"vulnerability","aliases":["CVE-2026-98491"],"related":[],"title":"Linux kernel: Open vSwitch conntrack use-after-free on cloned packets","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: conntrack: avoid modifying shared unconfirmed ct entry\n\nIn a case where skb with an unconfirmed ct entry gets cloned, we may\nend up committing both but with different sets of extensions.\n\nThe series of events:\n\n 1. The first clone wants to commit and runs the helpers wiring up\n    the extension pointer into the expectation list.\n 2. Then it looses the confirmation keeping the entry unconfirmed.\n 3. Second clone now wants to commit labels and adds the new extension\n    for that breaking the pointer in the expectation list causing\n    UAF on the destruction path later.\n\nWhile this is possible to trigger, there should be no practical\nnetwork pipeline where committing both clones without modifications\ninto the same zone is needed.  So, let's just reset the entry in case\nfor some reason we got an skb with a shared one during commit.  This\ndoesn't affect any known use cases, but avoids any potential problems\nwith sharing and modification of the unconfirmed ct entry.\n\nThe fixes tag points to the introduction of helpers, since that's the\nmain UAF trigger for the sharing.","summary":"In the Linux kernel's Open vSwitch conntrack code, a cloned packet with an unconfirmed connection entry can be committed twice with different extensions, leaving a dangling pointer. Freeing that pointer later is a use-after-free, which the sources do not say an attacker can turn into code execution.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["conntrack","kubernetes","linux-kernel","open-vswitch","package","self-hosted"],"not_affected_if":["unknown"],"how_to_check":"- unknown","fix":"- unknown","status":"open","published_at":"2026-10-18T16:17:00+00:00","first_seen_at":"2026-10-23T21:57:15+00:00","triaged_at":"2026-10-25T05:25:41+00:00","updated_at":"2026-10-25T05:25:41+00:00","category":"package","confidence":0.5,"triage":{"at":"2026-10-25T05:25:41Z","model":"claude-haiku-5-5","output":{"fix":"- unknown","reach":"unknown","title":"Linux kernel: Open vSwitch conntrack use-after-free on cloned packets","impact":"high","summary":"In the Linux kernel's Open vSwitch conntrack code, a cloned packet with an unconfirmed connection entry can be committed twice with different extensions, leaving a dangling pointer. Freeing that pointer later is a use-after-free, which the sources do not say an attacker can turn into code execution.","category":"package","nicknames":[],"who_cares":["linux-kernel","open-vswitch","conntrack","self-hosted","kubernetes"],"confidence":0.5,"needs_auth":"unknown","worst_case":"Kernel memory corruption via use-after-free on the destruction path","analyst_note":"Check the upstream kernel stable commit and the NVD entry for affected version ranges, and whether a fixed kernel release is named.","how_to_check":"- unknown","needs_analyst":true,"not_affected_if":["unknown"],"who_is_affected":"Hosts running a Linux kernel with the Open vSwitch module and conntrack commit actions in use, such as Open vSwitch datapath setups with conntrack zones. unknown whether the sources name affected kernel version ranges or whether default configurations trigger it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.0006,"input_tokens":3594,"output_tokens":481,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':14A,17A '-98491':15A,18A '1':129C '2':149C '3':159C 'add':168C 'affect':238C 'attack':76B 'avoid':95C,244C 'break':174C 'case':103C,221C,242C 'caus':181C 'clone':11A,41B,112C,132C,161C,204C 'code':39B,80B 'commit':50B,117C,135C,165C,202C,234C 'confirm':154C 'connect':46B 'conntrack':5A,19B,38B,94C 'ct':99C,109C,255C 'cve':13A,16A 'dangl':57B 'destruct':185C 'differ':53B,121C 'doesn':236C 'end':115C 'entri':47B,100C,110C,157C,219C,256C 'event':128C 'execut':81B 'expect':147C,179C 'extens':54B,124C,143C,171C 'first':131C 'fix':258C 'follow':87C 'free':9A,59B,68B 'get':111C 'got':226C 'helper':139C,265C 'host':30B 'introduct':263C 'keep':155C 'kernel':2A,23B,34B,85C 'known':240C 'kubernet':20B 'label':166C 'later':62B,187C 'leav':55B 'let':214C 'linux':1A,22B,33B,84C 'linux-kernel':21B 'list':148C,180C 'loos':152C 'main':270C 'may':114C 'modif':206C,251C 'modifi':96C 'need':212C 'net':92C 'network':199C 'new':170C 'one':232C 'open':3A,25B,36B 'open-vswitch':24B 'openvswitch':93C 'packag':27B 'packet':12A,42B 'path':186C 'pipelin':200C 'point':260C 'pointer':58B,61B,144C,176C 'possibl':191C 'potenti':246C 'practic':198C 'problem':247C 'reason':224C 'reset':217C 'resolv':91C 'run':137C 'say':74B 'second':160C 'self':29B 'self-host':28B 'seri':126C 'set':122C 'share':97C,231C,249C,275C 'sinc':266C 'skb':105C,228C 'sourc':71B 'tag':259C 'trigger':193C,272C 'turn':78B 'twice':51B 'uaf':182C,271C 'unconfirm':45B,98C,108C,158C,254C 'use':7A,66B,241C 'use-after-fre':6A,65B 'vswitch':4A,26B,37B 'vulner':88C 'want':133C,163C 'wire':140C 'without':205C 'zone':210C","nicknames":[],"mitigations":[],"who_affected":"Hosts running a Linux kernel with the Open vSwitch module and conntrack commit actions in use, such as Open vSwitch datapath setups with conntrack zones. unknown whether the sources name affected kernel version ranges or whether default configurations trigger it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-18T16:17:00+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98491","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98491","severity":null,"published_at":"2026-10-18T16:17:00+00:00","modified_at":"2026-10-19T10:19:01+00:00","first_seen_at":"2026-10-23T21:57:15+00:00","fetched_at":"2026-10-23T22:28:56+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"}