{"id":"CVE-2026-116539","kind":"vulnerability","aliases":["CVE-2026-116539"],"related":[],"title":"Netty tcnative: remote TLS peer can crash JVM via heap overflow","description":"Netty netty-tcnative before 2.0.84.Final contains a heap buffer overflow vulnerability in the tcn_write_to_bytebuffer BIO callback caused by failing to wrap the non-application ring buffer write index. Remote TLS peers can drive handshake, renegotiation, or post-handshake messages into this buffer, triggering an out-of-bounds memcpy that crashes the JVM process.","summary":"Netty's netty-tcnative library, before 2.0.84.Final, has a heap buffer overflow in its BIO write callback during TLS handshake, renegotiation, or post-handshake messages. A remote TLS peer can trigger an out-of-bounds memcpy that crashes the JVM process.","severity":"high","cvss":8.2,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["java","jvm","netty","package","tls"],"not_affected_if":["jdk-tls-provider","no-tcnative-dependency"],"how_to_check":"- Check the netty-tcnative version in the project's dependency tree, for example with `mvn dependency:tree | grep tcnative` or `gradle dependencies | grep tcnative`\n- Look for `netty-tcnative` or `netty-tcnative-boringssl-static` in the lock file or the packaged application","fix":"- Upgrade netty-tcnative to `2.0.84.Final` or later\n- Rebuild and redeploy the application so the new version ships in its artifact","status":"open","published_at":"2026-10-26T16:17:19+00:00","first_seen_at":"2026-10-26T16:31:01+00:00","triaged_at":"2026-10-26T16:32:47+00:00","updated_at":"2026-10-26T16:32:47+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-26T16:32:47Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade netty-tcnative to `2.0.84.Final` or later\n- Rebuild and redeploy the application so the new version ships in its artifact","reach":"internet","title":"Netty tcnative: remote TLS peer can crash JVM via heap overflow","impact":"medium","summary":"Netty's netty-tcnative library, before 2.0.84.Final, has a heap buffer overflow in its BIO write callback during TLS handshake, renegotiation, or post-handshake messages. A remote TLS peer can trigger an out-of-bounds memcpy that crashes the JVM process.","category":"package","nicknames":[],"who_cares":["java","netty","tls","jvm"],"confidence":0.6,"needs_auth":"no","worst_case":"Remote peer crashes the JVM process via heap overflow","analyst_note":"Sources give no exploit details, affected version range beyond 'before 2.0.84.Final', or confirmation of crash-only impact; check the Netty security advisory for the exact affected range and whether code execution is possible.","how_to_check":"- Check the netty-tcnative version in the project's dependency tree, for example with `mvn dependency:tree | grep tcnative` or `gradle dependencies | grep tcnative`\n- Look for `netty-tcnative` or `netty-tcnative-boringssl-static` in the lock file or the packaged application","needs_analyst":true,"not_affected_if":["jdk-tls-provider","no-tcnative-dependency"],"who_is_affected":"Java services that use Netty with the tcnative (BoringSSL/OpenSSL) TLS backend and accept TLS connections from untrusted peers are exposed. Applications using the JDK TLS provider instead of tcnative, or services only reachable by trusted clients, have lower exposure.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000662,"input_tokens":3356,"output_tokens":653,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-116539':14A,17A '-2026':13A,16A '2.0.84.final':30B,72C 'applic':95C 'bio':38B,85C 'bound':60B,120C 'buffer':34B,76C,97C,114C 'bytebuff':84C 'callback':40B,86C 'caus':87C 'contain':73C 'crash':7A,63B,123C 'cve':12A,15A 'drive':104C 'fail':89C 'handshak':43B,48B,105C,110C 'heap':10A,33B,75C 'index':99C 'java':18B 'jvm':8A,19B,65B,125C 'librari':28B 'memcpi':61B,121C 'messag':49B,111C 'netti':1A,20B,23B,26B,67C,69C 'netty-tcn':25B,68C 'non':94C 'non-appl':93C 'out-of-bound':57B,117C 'overflow':11A,35B,77C 'packag':21B 'peer':5A,53B,102C 'post':47B,109C 'post-handshak':46B,108C 'process':66B,126C 'remot':3A,51B,100C 'renegoti':44B,106C 'ring':96C 'tcn':81C 'tcnativ':2A,27B,70C 'tls':4A,22B,42B,52B,101C 'trigger':55B,115C 'via':9A 'vulner':78C 'wrap':91C 'write':39B,82C,98C","nicknames":[],"mitigations":[],"who_affected":"Java services that use Netty with the tcnative (BoringSSL/OpenSSL) TLS backend and accept TLS connections from untrusted peers are exposed. Applications using the JDK TLS provider instead of tcnative, or services only reachable by trusted clients, have lower exposure.","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-2026-116539","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-116539","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"}