{"id":"CVE-2026-98805","kind":"vulnerability","aliases":["CVE-2026-98805"],"related":[],"title":"Linux kernel TIPC: peer key change lets AES-GCM nonces repeat","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: prevent GCM nonce reuse on peer key changes\n\nTIPC can encrypt traffic between nodes using a different transmit key\nfor each node. In this mode, the AES-GCM nonce for a packet sent to a\nknown peer consists of a 32-bit prefix (a per-key salt XOR the peer's\naddress) followed by a 64-bit counter. That counter is stored in the\npeer's RX crypto object. When the peer reports a change in which key\nit uses to receive packets, TIPC resets this counter. The sender can\nstill be using the same TX key and salt, so subsequent packets reuse\nearlier nonces. This nonce reuse breaks confidentiality and exposes\nGCM's authentication key. This makes forgeries trivial: an attacker\ncan exploit CTR malleability to alter captured ciphertexts and use the\nrecovered authentication key to compute a valid tag for the modified\nciphertext, under the same key and nonce.\n\nUse the TX key's existing aead->seqno counter instead. All encryptions\nusing that key object share the same atomic counter, so concurrent\nencryptions get distinct nonce counter values. The counter survives\nkey activation and peer reconnection, and peer key-status reports\ncannot reset it. This prevents those transitions from causing nonce\nreuse while the same TX key remains installed.\n\nThe nonce format is unchanged, and receivers do not require consecutive\ncounter values, so sharing the counter across peers remains compatible\nwith existing receivers. A pre-existing check still invokes key\nrevocation in the unlikely event that the counter wraps to zero.","summary":"When a TIPC peer reports a key change, the kernel resets the counter used in AES-GCM nonces, so the same key and nonce can be reused on later packets. Reused GCM nonces can let an attacker recover the authentication key and forge valid tags for modified traffic.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["cluster-nodes","linux-kernel","runtime","tipc"],"not_affected_if":["no-tipc-usage"],"how_to_check":"- unknown","fix":"- unknown","status":"open","published_at":"2026-10-18T16:17:34+00:00","first_seen_at":"2026-10-23T21:57:16+00:00","triaged_at":"2026-10-25T05:15:01+00:00","updated_at":"2026-10-25T05:15:01+00:00","category":"runtime","confidence":0.5,"triage":{"at":"2026-10-25T05:15:01Z","model":"claude-haiku-5-5","output":{"fix":"- unknown","reach":"network","title":"Linux kernel TIPC: peer key change lets AES-GCM nonces repeat","impact":"high","summary":"When a TIPC peer reports a key change, the kernel resets the counter used in AES-GCM nonces, so the same key and nonce can be reused on later packets. Reused GCM nonces can let an attacker recover the authentication key and forge valid tags for modified traffic.","category":"runtime","nicknames":[],"who_cares":["linux-kernel","tipc","cluster-nodes"],"confidence":0.5,"needs_auth":"unknown","worst_case":"Attacker forges encrypted cluster traffic and reads or alters captured packets","analyst_note":"Find the affected kernel version range and the fixed commit from the NVD entry or the kernel stable tree, and confirm whether TIPC encryption requires explicit configuration.","how_to_check":"- unknown","needs_analyst":true,"not_affected_if":["no-tipc-usage"],"who_is_affected":"Systems running a Linux kernel with TIPC (Transparent Inter-Process Communication) cluster encryption enabled between nodes are the ones exposed. The sources do not say which kernel versions are affected or whether TIPC encryption is on by default, so teams without TIPC clusters can likely skip it, but the sources do not confirm that.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000629,"input_tokens":3755,"output_tokens":507,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':14A,17A '-98805':15A,18A '32':128C '64':144C 'across':318C 'activ':273C 'address':140C 'ae':9A,43B,114C 'aead':246C 'aes-gcm':8A,42B,113C 'alter':216C 'atom':259C 'attack':64B,210C 'authent':67B,203C,223C 'bit':129C,145C 'break':197C 'cannot':283C 'captur':217C 'caus':291C 'chang':6A,34B,94C,163C 'check':329C 'ciphertext':218C,233C 'cluster':20B 'cluster-nod':19B 'compat':321C 'comput':226C 'concurr':262C 'confidenti':198C 'consecut':311C 'consist':125C 'counter':39B,146C,148C,175C,248C,260C,267C,270C,312C,317C,340C 'crypto':156C 'ctr':213C 'cve':13A,16A 'differ':103C 'distinct':265C 'earlier':192C 'encrypt':97C,251C,263C 'event':337C 'exist':245C,323C,328C 'exploit':212C 'expos':200C 'follow':81C,141C 'forg':70B 'forgeri':207C 'format':303C 'gcm':10A,44B,59B,88C,115C,201C 'get':264C 'instal':300C 'instead':249C 'invok':331C 'kernel':2A,24B,36B,79C 'key':5A,33B,49B,68B,93C,105C,134C,166C,185C,204C,224C,237C,243C,254C,272C,280C,298C,332C 'key-status':279C 'known':123C 'later':56B 'let':7A,62B 'linux':1A,23B,78C 'linux-kernel':22B 'make':206C 'malleabl':214C 'mode':111C 'modifi':74B,232C 'node':21B,100C,108C 'nonc':11A,45B,51B,60B,89C,116C,193C,195C,239C,266C,292C,302C 'object':157C,255C 'packet':57B,119C,171C,190C 'peer':4A,30B,92C,124C,138C,153C,160C,275C,278C,319C 'per':133C 'per-key':132C 'pre':327C 'pre-exist':326C 'prefix':130C 'prevent':87C,287C 'receiv':170C,307C,324C 'reconnect':276C 'recov':65B,222C 'remain':299C,320C 'repeat':12A 'report':31B,161C,282C 'requir':310C 'reset':37B,173C,284C 'resolv':85C 'reus':54B,58B,90C,191C,196C,293C 'revoc':333C 'runtim':25B 'rx':155C 'salt':135C,187C 'sender':177C 'sent':120C 'seqno':247C 'share':256C,315C 'status':281C 'still':179C,330C 'store':150C 'subsequ':189C 'surviv':271C 'tag':72B,229C 'tipc':3A,26B,29B,86C,95C,172C 'traffic':75B,98C 'transit':289C 'transmit':104C 'trivial':208C 'tx':184C,242C,297C 'unchang':305C 'unlik':336C 'use':40B,101C,168C,181C,220C,240C,252C 'valid':71B,228C 'valu':268C,313C 'vulner':82C 'wrap':341C 'xor':136C 'zero':343C","nicknames":[],"mitigations":[],"who_affected":"Systems running a Linux kernel with TIPC (Transparent Inter-Process Communication) cluster encryption enabled between nodes are the ones exposed. The sources do not say which kernel versions are affected or whether TIPC encryption is on by default, so teams without TIPC clusters can likely skip it, but the sources do not confirm that.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-18T16:17:34+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98805","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98805","severity":null,"published_at":"2026-10-18T16:17:34+00:00","modified_at":"2026-10-21T13:21:47+00:00","first_seen_at":"2026-10-23T21:57:16+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"}