Missing Validation in s2n-tls Affects TLS 1.3 Connections

CVE-2026-16317

What is CVE-2026-16317?

A flaw in the s2n-tls implementation of TLS 1.3 permits an attacker to execute a man-in-the-middle attack that silently discards application data. Due to the lack of proper validation of the outer content_type byte in encrypted records, an attacker can manipulate the transmission without detection, leading to potential application data loss and miscommunication between clients and servers. This vulnerability particularly impacts HTTP pipelining scenarios and write-heavy workloads, risking undetectable data loss and desynchronization of requests and responses. To ensure security, upgrade to s2n-tls version v1.7.6.

References