What’s Vulnerable › Vulnerabilities

CVE-2026-116541: netty-tcnative before 2.0.84.Final Denial of Service via BIO Write Overcount

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% 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-682

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.

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#L240
• https://github.com/netty/netty-tcnative/commit/e31df4a5885b35085fdfa3e2dca7c1f705d4745b
• https://github.com/netty/netty-tcnative/releases/tag/netty-tcnative-parent-2.0.84.Final
• https://github.com/netty/netty-tcnative/security/advisories/GHSA-9xr3-jwv4-r489
• https://www.vulncheck.com/advisories/netty-tcnative-before-2.0.84-final-denial-of-service-via-bio-write-overcount

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