Silent record suppression via unauthenticated outer content type
Published Jul 21, 2026 · Updated Jul 21, 2026
Improper integrity validation in s2n-tls 1.7.5 and earlier allows man-in-the-middle attackers to suppress TLS 1.3 records. The AEAD record handler hardcodes application_data in the additional authenticated data and fails to validate the outer content_type wire byte before dispatch. An active network position on a TLS 1.3 client or server connection is required; selective drops can desynchronize pipelined HTTP exchanges or cause undetected data loss.
Summary
What happened
Improper integrity validation in s2n-tls 1.7.5 and earlier allows man-in-the-middle attackers to suppress TLS 1.3 records. The AEAD record handler hardcodes application_data in the additional authenticated data and fails to validate the outer content_type wire byte before dispatch. An active network position on a TLS 1.3 client or server connection is required; selective drops can desynchronize pipelined HTTP exchanges or cause undetected data loss.
The record
- CVE
- CVE-2026-16317
- Published
- Jul 21, 2026
- Updated
- Jul 21, 2026
- Vendor
- Amazon Web Services
- Product
- s2n-tls
- Classifications
- CWE-354, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 21, 2026CVE publishedPublication date reported by the CVE source.
- Jul 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=1.7.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo