{"id":"CVE-2026-99066","kind":"vulnerability","aliases":["CVE-2026-99066"],"related":[],"title":"Linux kernel: CAN RX skbs can panic the machine via SOCK_PACKET","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: dev: init_can_skb(): restore skb header initialization\n\nCommit 9f10374bb024 (\"can: remove private CAN skb headroom infrastructure\")\nremoved the skb_reset_mac_header()/skb_reset_network_header()/\nskb_reset_transport_header() calls from init_can_skb(). As a result, RX\nskbs from alloc_can_skb() and friends again carry mac_header = 0xFFFF.\nWhen such an skb reaches packet_rcv_spkt() (SOCK_PACKET), the push length\ncalculation overflows and triggers skb_under_panic -> kernel BUG -> full\nmachine panic.\n\nThe same issue was originally reported in 2014 on linux-can and fixed by\ncommit 969439016d2c (\"can: add missing initialisations in CAN related\nskbuffs\"). packet_rcv_spkt() itself has never been hardened: only\npacket_rcv() and tpacket_rcv() gained dev_has_header() checks in\ncommit d549699048b4 (\"net/packet: fix packet receive on L3 devices\nwithout visible hard header\").","summary":"Linux CAN RX socket buffers are created without their MAC and network header offsets, so a SOCK_PACKET receiver can overflow a length calculation and hit a kernel BUG. The result is a full machine panic, which an attacker can trigger by sending CAN traffic to a host that has a SOCK_PACKET listener.","severity":"unknown","cvss":null,"epss":0.00198,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["can-bus","embedded","linux-kernel","runtime","self-hosted"],"not_affected_if":["no-can-interfaces","no-sock-packet-listeners"],"how_to_check":"- unknown","fix":"- Move the Linux kernel to a release that includes the fix for CVE-2026-99066 (version unknown from the sources)\n- unknown","status":"open","published_at":"2026-10-23T13:17:30+00:00","first_seen_at":"2026-10-23T21:57:34+00:00","triaged_at":"2026-10-25T04:53:50+00:00","updated_at":"2026-10-25T12:38:50+00:00","category":"runtime","confidence":0.5,"triage":{"at":"2026-10-25T04:53:50Z","model":"claude-haiku-5-5","output":{"fix":"- Move the Linux kernel to a release that includes the fix for CVE-2026-99066 (version unknown from the sources)\n- unknown","reach":"network","title":"Linux kernel: CAN RX skbs can panic the machine via SOCK_PACKET","impact":"medium","summary":"Linux CAN RX socket buffers are created without their MAC and network header offsets, so a SOCK_PACKET receiver can overflow a length calculation and hit a kernel BUG. The result is a full machine panic, which an attacker can trigger by sending CAN traffic to a host that has a SOCK_PACKET listener.","category":"runtime","nicknames":[],"who_cares":["linux-kernel","can-bus","embedded","self-hosted"],"confidence":0.5,"needs_auth":"unknown","worst_case":"Kernel panic takes the whole machine down","analyst_note":"Find the fixed kernel versions and the stable commit for the CAN init_can_skb() fix at https://nvd.nist.gov/vuln/detail/CVE-2026-99066.","how_to_check":"- unknown","needs_analyst":true,"not_affected_if":["no-can-interfaces","no-sock-packet-listeners"],"who_is_affected":"Hosts running a Linux kernel with CAN support where something opens a SOCK_PACKET socket on a CAN interface. Systems without CAN devices or without SOCK_PACKET listeners are unlikely to be exposed, but the sources do not say which kernel versions are affected.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000638,"input_tokens":3596,"output_tokens":557,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':14A,17A '-99066':15A,18A '/skb_reset_network_header':118C '0xffff':143C '2014':176C '969439016d2c':185C '9f10374bb024':104C 'add':187C 'alloc':134C 'attack':68B 'buffer':34B 'bug':58B,165C 'bus':21B 'calcul':53B,157C 'call':123C 'can-bus':19B 'carri':140C 'check':212C 'commit':103C,184C,214C 'creat':36B 'cve':13A,16A 'd549699048b4':215C 'dev':95C,209C 'devic':222C 'embed':22B 'fix':182C,217C 'follow':89C 'friend':138C 'full':63B,166C 'gain':208C 'hard':225C 'harden':201C 'header':42B,101C,117C,122C,142C,211C,226C 'headroom':110C 'hit':55B 'host':29B,77B 'infrastructur':111C 'init':96C,125C 'initi':102C 'initialis':189C 'issu':171C 'kernel':2A,25B,57B,87C,164C 'l3':221C 'length':52B,156C 'linux':1A,24B,30B,86C,179C 'linux-can':178C 'linux-kernel':23B 'listen':83B 'mac':39B,116C,141C 'machin':9A,64B,167C 'miss':188C 'net/packet':216C 'network':41B 'never':199C 'offset':43B 'origin':173C 'overflow':50B,158C 'packet':12A,47B,82B,149C,153C,194C,203C,218C 'panic':7A,65B,163C,168C 'privat':107C 'push':155C 'rcv':150C,195C,204C,207C 'reach':148C 'receiv':48B,219C 'relat':192C 'remov':106C,112C 'report':174C 'reset':115C,120C 'resolv':93C 'restor':99C 'result':60B,130C 'runtim':26B 'rx':4A,32B,131C 'self':28B 'self-host':27B 'send':72B 'skb':98C,100C,109C,114C,119C,127C,136C,147C,161C 'skbs':5A,132C 'skbuff':193C 'sock':11A,46B,81B,152C 'socket':33B 'spkt':151C,196C 'tpacket':206C 'traffic':74B 'transport':121C 'trigger':70B,160C 'via':10A 'visibl':224C 'vulner':90C 'without':37B,223C","nicknames":[],"mitigations":[],"who_affected":"Hosts running a Linux kernel with CAN support where something opens a SOCK_PACKET socket on a CAN interface. Systems without CAN devices or without SOCK_PACKET listeners are unlikely to be exposed, but the sources do not say which kernel versions are affected.","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-2026-99066","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99066","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},{"source":"epss","external_id":"CVE-2026-99066","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-99066","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"}