{"id":"CVE-2026-116541","kind":"vulnerability","aliases":["CVE-2026-116541"],"related":[],"title":"Netty tcnative: remote TLS 1.3 peers can crash Java processes","description":"Netty netty-tcnative before 2.0.84.Final contains a denial of service vulnerability in the tcn_write_to_bytebuffer BIO write callback that overreports bytes consumed. Remote TLS 1.3 peers can provoke queued post-handshake records like NewSessionTicket or KeyUpdate to truncate flights, fail connections, or abort the JVM process.","summary":"Netty's netty-tcnative library overreports bytes consumed in its TLS write callback, so queued post-handshake records such as NewSessionTicket or KeyUpdate can be mishandled. A remote TLS 1.3 peer can use this to truncate handshake flights, fail connections, or abort the JVM process.","severity":"high","cvss":8.2,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["java","jvm-servers","netty","package","tls"],"not_affected_if":["jdk-ssl-provider","no-tls-listener"],"how_to_check":"- Find netty-tcnative in the build file or dependency tree and check whether its version is below `2.0.84.Final`.\n- Confirm whether the service uses netty-tcnative as its TLS provider, since the flaw is in that library's BIO write callback.","fix":"- Upgrade netty-tcnative to `2.0.84.Final` or later.\n- Rebuild and redeploy services that bundle the library.","status":"open","published_at":"2026-10-26T16:17:19+00:00","first_seen_at":"2026-10-26T16:31:01+00:00","triaged_at":"2026-10-26T16:32:51+00:00","updated_at":"2026-10-26T16:32:51+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-26T16:32:51Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade netty-tcnative to `2.0.84.Final` or later.\n- Rebuild and redeploy services that bundle the library.","reach":"internet","title":"Netty tcnative: remote TLS 1.3 peers can crash Java processes","impact":"high","summary":"Netty's netty-tcnative library overreports bytes consumed in its TLS write callback, so queued post-handshake records such as NewSessionTicket or KeyUpdate can be mishandled. A remote TLS 1.3 peer can use this to truncate handshake flights, fail connections, or abort the JVM process.","category":"package","nicknames":[],"who_cares":["netty","java","tls","jvm-servers"],"confidence":0.6,"needs_auth":"no","worst_case":"Remote peers crash the JVM process or fail connections.","analyst_note":"","how_to_check":"- Find netty-tcnative in the build file or dependency tree and check whether its version is below `2.0.84.Final`.\n- Confirm whether the service uses netty-tcnative as its TLS provider, since the flaw is in that library's BIO write callback.","needs_analyst":false,"not_affected_if":["jdk-ssl-provider","no-tls-listener"],"who_is_affected":"Java services that terminate TLS through Netty with the netty-tcnative (BoringSSL-backed) provider and accept connections from remote peers are exposed. Services using only the JDK TLS provider, or no TLS listener, are not in the described path.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.001069,"input_tokens":3356,"output_tokens":1466,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-116541':13A,16A '-2026':12A,15A '1.3':5A,55B,98C '2.0.84.final':76C 'abort':67B,117C 'bio':89C 'byte':31B,94C 'bytebuff':88C 'callback':37B,91C 'connect':65B,115C 'consum':32B,95C 'contain':77C 'crash':8A 'cve':11A,14A 'denial':79C 'fail':64B,114C 'flight':63B,113C 'handshak':42B,62B,105C 'java':9A,17B 'jvm':19B,69B,119C 'jvm-server':18B 'keyupd':48B,110C 'librari':29B 'like':107C 'mishandl':51B 'netti':1A,21B,24B,27B,71C,73C 'netty-tcn':26B,72C 'newsessionticket':46B,108C 'overreport':30B,93C 'packag':22B 'peer':6A,56B,99C 'post':41B,104C 'post-handshak':40B,103C 'process':10A,70B,120C 'provok':101C 'queu':39B,102C 'record':43B,106C 'remot':3A,53B,96C 'server':20B 'servic':81C 'tcn':85C 'tcnativ':2A,28B,74C 'tls':4A,23B,35B,54B,97C 'truncat':61B,112C 'use':58B 'vulner':82C 'write':36B,86C,90C","nicknames":[],"mitigations":[],"who_affected":"Java services that terminate TLS through Netty with the netty-tcnative (BoringSSL-backed) provider and accept connections from remote peers are exposed. Services using only the JDK TLS provider, or no TLS listener, are not in the described path.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-26T16:17:19+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-116541","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-116541","severity":null,"published_at":"2026-10-26T16:17:19+00:00","modified_at":"2026-10-26T16:17:19+00:00","first_seen_at":"2026-10-26T16:31:01+00:00","fetched_at":"2026-10-26T16:31:01+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"}