Buffer overflow in Netty Netty-Tcnative
CVE-2026-116539
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/netty/netty-tcnative/security/advisories/GHSA-gf9q-9mg7-g5qh (vendor-advisory)
- github.com/netty/netty-tcnative/commit/92dd66fd1243d85c05a61288f96367a70260b6b8 (patch)
- github.com/netty/netty-tcnative/blob/netty-tcnative-parent-2.0.83.Final/openssl… (technical-description)
- github.com/netty/netty-tcnative/releases/tag/netty-tcnative-parent-2.0.84.Final (release-notes)
- github.com/netty/netty-tcnative (product)
- www.vulncheck.com/advisories/netty-netty-tcnative-before-2.0.84-final-heap-buff… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-116539?
- CVE-2026-116539 is a medium-severity vulnerability in Netty Netty-Tcnative, classified under Out-of-bounds Write. CVSS score: 5.9/10. Published 2026-10-26.
- How severe is CVE-2026-116539?
- Medium severity. CVSS v3 base score is 5.9 out of 10.