{"id":"CVE-2026-99064","kind":"vulnerability","aliases":["CVE-2026-99064"],"related":[],"title":"Linux kernel: CIPSO option removal leaves stale offsets, corrupting IP options","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncipso: adjust cached option offsets when removing CIPSO\n\ncipso_v4_skbuff_delattr() removes the CIPSO bytes but does not adjust\ncached offsets for options that follow them.\n\nFor example, with a valid 10-byte CIPSO option followed by a seven-byte\nRR option, parsing records rr at offset 30.  Removing CIPSO moves RR to\noffset 20, while the cached offset remains 30.  Consumers such as\nip_forward_options() and __ip_options_echo() then access the wrong bytes;\nthe latter may interpret packet data as the option length and copy it into\nfixed-size option storage.\n\nMirror cipso_v4_delopt() and subtract cipso_len from the srr, rr, ts and\nrouter_alert offsets when they follow CIPSO.  cipso_len is the distance\nthe first memmove() shifts those options.  The later header move and\nnetwork-header reset relocate the bytes and their offset base together.","summary":"When the Linux kernel removes a CIPSO option from a packet, it does not adjust cached offsets for IP options that follow it, so later code reads the wrong bytes. The sources do not say what an attacker gets beyond corrupted option handling, though the description notes that option copying may treat packet data as a length and write it into fixed-size storage.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["cipso","infrastructure","ip-options","kernel","linux"],"not_affected_if":[],"how_to_check":"- unknown","fix":"- unknown","status":"open","published_at":"2026-10-23T13:17:30+00:00","first_seen_at":"2026-10-23T21:57:34+00:00","triaged_at":"2026-10-25T04:53:51+00:00","updated_at":"2026-10-25T04:53:51+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-10-25T04:53:51Z","model":"claude-haiku-5-5","output":{"fix":"- unknown","reach":"network","title":"Linux kernel: CIPSO option removal leaves stale offsets, corrupting IP options","impact":"medium","summary":"When the Linux kernel removes a CIPSO option from a packet, it does not adjust cached offsets for IP options that follow it, so later code reads the wrong bytes. The sources do not say what an attacker gets beyond corrupted option handling, though the description notes that option copying may treat packet data as a length and write it into fixed-size storage.","category":"infrastructure","nicknames":[],"who_cares":["linux","kernel","ip-options","cipso"],"confidence":0.5,"needs_auth":"unknown","worst_case":"unknown; may corrupt kernel IP option handling and copy packet data","analyst_note":"Check the NVD entry and the upstream kernel stable commit for affected kernel version ranges and the fixed versions, and whether CIPSO is enabled by default.","how_to_check":"- unknown","needs_analyst":true,"not_affected_if":[],"who_is_affected":"unknown","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000559,"input_tokens":3545,"output_tokens":409,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-99064':14A,17A '10':132C '20':156C '30':149C,162C 'access':174C 'adjust':39B,101C,119C 'alert':212C 'attack':62B 'base':244C 'beyond':64B 'byte':54B,115C,133C,141C,177C,240C 'cach':40B,102C,120C,159C 'cipso':3A,18B,31B,100C,107C,108C,114C,134C,151C,198C,203C,217C,218C 'code':50B 'consum':163C 'copi':74B,189C 'corrupt':9A,65B 'cve':12A,15A 'data':78B,183C 'delattr':111C 'delopt':200C 'descript':70B 'distanc':222C 'echo':172C 'exampl':128C 'first':224C 'fix':87B,193C 'fixed-s':86B,192C 'follow':46B,95C,125C,136C,216C 'forward':167C 'get':63B 'handl':67B 'header':231C,236C 'infrastructur':19B 'interpret':181C 'ip':10A,21B,43B,166C,170C 'ip-opt':20B 'kernel':2A,23B,28B,93C 'later':49B,230C 'latter':179C 'leav':6A 'len':204C,219C 'length':81B,187C 'linux':1A,24B,27B,92C 'may':75B,180C 'memmov':225C 'mirror':197C 'move':152C,232C 'network':235C 'network-head':234C 'note':71B 'offset':8A,41B,104C,121C,148C,155C,160C,213C,243C 'option':4A,11A,22B,32B,44B,66B,73B,103C,123C,135C,143C,168C,171C,186C,195C,228C 'packet':35B,77B,182C 'pars':144C 'read':51B 'record':145C 'reloc':238C 'remain':161C 'remov':5A,29B,106C,112C,150C 'reset':237C 'resolv':99C 'router':211C 'rr':142C,146C,153C,208C 'say':59B 'seven':140C 'seven-byt':139C 'shift':226C 'size':88B,194C 'skbuff':110C 'sourc':56B 'srr':207C 'stale':7A 'storag':89B,196C 'subtract':202C 'though':68B 'togeth':245C 'treat':76B 'ts':209C 'v4':109C,199C 'valid':131C 'vulner':96C 'write':83B 'wrong':53B,176C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-23T13:17:30+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-99064","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99064","severity":null,"published_at":"2026-10-23T13:17:30+00:00","modified_at":"2026-10-23T13:17:30+00:00","first_seen_at":"2026-10-23T21:57:34+00:00","fetched_at":"2026-10-23T22:29:03+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"}