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Missing validation of the outer content_type byte on TLS 1.3 encrypted records in s2n-tls allows an active man-in-the-middle to silently discard individual application data records without either end…

Medium CVSS 6.5
CVECVE-2026-16317
First seen2026-07-21 23:15 UTC
Disclosed2026-07-21 21:16 UTC
Last updated2026-07-21 23:15 UTC
Channel statusauto

Summary

Missing validation of the outer content_type byte on TLS 1.3 encrypted records in s2n-tls allows an active man-in-the-middle to silently discard individual application data records without either endpoint detecting the modification. RFC 8446 Section 5.2 requires that the outer content_type of all encrypted TLS 1.3 records must be application_data (0x17). The s2n-tls AEAD implementation hardcodes this value in the additional authenticated data rather than using the actual wire byte, so the outer…

In-depth triage · Auto channel

No in-depth report has been generated yet (DR-003 v2 AI pipeline is under construction).

Lint boundary warnings (1)

The following non-blocking warnings were raised during the lint phase of this triage (e.g. reference URLs not yet on the allowlist). They do not affect entry usability and are disclosed for transparency (see DR-002).

  • REF_URL_NOT_ALLOWLISTED url not in allowlist: https://aws.amazon.com/security/security-bulletins/2026-062-aws/

Sources

  • NVD DATABASE

Original Links

Timeline

  1. nvd_ingest NVD