Memory Leak Vulnerability in s2n-tls's QUIC Transport Parameters Handler

CVE-2026-16318

What is CVE-2026-16318?

The QUIC transport parameters extension handler in s2n-tls contains a flaw that leads to a memory leak during TLS 1.3 connections managed by HelloRetryRequests. When the handler is triggered a second time for the same connection, it erroneously utilizes s2n_alloc instead of s2n_realloc. This mistake results in the original memory pointer being set to zero, leading to unrecovered memory. Over time, this can result in significant memory consumption on servers running QUIC, suggesting a critical need for updates and monitoring in affected deployments.

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