What’s Vulnerable › Vulnerabilities

CVE-2026-116539: Netty netty-tcnative before 2.0.84.Final Heap Buffer Overflow via OpenSSL BIO

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-26 · updated 2026-10-26
• Weakness: CWE-787

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.

Affected products

• netty-tcnative: before 2.0.84.Final — fixed in 2.0.84.Final
• netty-tcnative-boringssl-static: before 2.0.84.Final — fixed in 2.0.84.Final

How to fix

Upgrade to a fixed version: netty-tcnative 2.0.84.Final; netty-tcnative-boringssl-static 2.0.84.Final. Check the vendor advisory for mitigations.

References

• https://github.com/netty/netty-tcnative
• https://github.com/netty/netty-tcnative/blob/netty-tcnative-parent-2.0.83.Final/openssl-dynamic/src/main/c/ssl.c#L199
• https://github.com/netty/netty-tcnative/commit/92dd66fd1243d85c05a61288f96367a70260b6b8
• https://github.com/netty/netty-tcnative/releases/tag/netty-tcnative-parent-2.0.84.Final
• https://github.com/netty/netty-tcnative/security/advisories/GHSA-gf9q-9mg7-g5qh
• https://www.vulncheck.com/advisories/netty-netty-tcnative-before-2.0.84-final-heap-buffer-overflow-via-openssl-bio

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