CVE-2026-16318

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Source
https://cve.org/CVERecord?id=CVE-2026-16318
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-16318.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-16318
Aliases
  • GHSA-cr7x-863j-xrc7
Published
2026-07-21T20:14:02.363Z
Modified
2026-07-22T05:32:10.001853018Z
Severity
  • 6.9 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N CVSS Calculator
Summary
QUIC Transport Parameters Memory Leak During HelloRetryRequest in s2n-tls
Details

The QUIC transport parameters extension handler in s2n-tls incorrectly uses s2nalloc instead of s2nrealloc to store the peer's transport parameters. When a TLS 1.3 connection goes through a HelloRetryRequest, the handler is called twice on the same connection. On the second call, s2n_alloc zeroes the existing pointer before allocating new memory, causing the first allocation to be leaked.

This can occur during normal QUIC traffic when a client offers a key share group the server does not prefer. An unauthenticated user can amplify the issue by deliberately forcing HelloRetryRequests, causing up to approximately 64 KB of unreachable memory per handshake. Over time, this can lead to increased memory consumption on long-running server processes. The unreachable memory is only reclaimed when the process is restarted.

Only server-side QUIC-enabled deployments are affected. Non-QUIC TLS connections are not affected.

We recommend you upgrade s2n-tls to version v1.7.6

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/16xxx/CVE-2026-16318.json",
    "cna_assigner": "AMZN",
    "cwe_ids": [
        "CWE-401"
    ]
}
References

Affected packages

Git / github.com/aws/s2n-tls

Affected ranges

Type
GIT
Repo
https://github.com/aws/s2n-tls
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Last affected
f5f6c6c2ce2370de1aa3ade6899a7321d1127bb8
Database specific 
{
    "source": "AFFECTED_FIELD",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "last_affected": "v1.7.5"
        }
    ]
}

Affected versions

0.*
0.10.24
1.*
1.0.3
1.3.19
1.7.1
v0.*
v0.10.0
v0.10.1
v0.10.10
v0.10.11
v0.10.12
v0.10.13
v0.10.14
v0.10.15
v0.10.16
v0.10.17
v0.10.18
v0.10.19
v0.10.2
v0.10.20
v0.10.21
v0.10.22
v0.10.23
v0.10.24
v0.10.25
v0.10.26
v0.10.3
v0.10.4
v0.10.5
v0.10.6
v0.10.7
v0.10.8
v0.10.9
v0.9.0
v1.*
v1.0.0
v1.0.1
v1.0.10
v1.0.11
v1.0.12
v1.0.13
v1.0.14
v1.0.15
v1.0.16
v1.0.17
v1.0.18
v1.0.19
v1.0.2
v1.0.4
v1.0.5
v1.0.8
v1.0.9
v1.1.0
v1.1.1
v1.1.2
v1.2.0
v1.2.1
v1.3.0
v1.3.1
v1.3.10
v1.3.11
v1.3.12
v1.3.13
v1.3.14
v1.3.15
v1.3.16
v1.3.17
v1.3.18
v1.3.19
v1.3.2
v1.3.20
v1.3.21
v1.3.22
v1.3.23
v1.3.24
v1.3.25
v1.3.26
v1.3.27
v1.3.28
v1.3.29
v1.3.3
v1.3.30
v1.3.31
v1.3.32
v1.3.33
v1.3.34
v1.3.35
v1.3.36
v1.3.37
v1.3.38
v1.3.39
v1.3.4
v1.3.40
v1.3.41
v1.3.42
v1.3.43
v1.3.44
v1.3.45
v1.3.46
v1.3.47
v1.3.48
v1.3.49
v1.3.5
v1.3.50
v1.3.51
v1.3.52
v1.3.53
v1.3.54
v1.3.55
v1.3.56
v1.3.6
v1.3.7
v1.3.8
v1.3.9
v1.4.0
v1.4.1
v1.4.10
v1.4.11
v1.4.12
v1.4.13
v1.4.14
v1.4.15
v1.4.16
v1.4.17
v1.4.18
v1.4.2
v1.4.3
v1.4.4
v1.4.5
v1.4.6
v1.4.7
v1.4.8
v1.4.9
v1.5.0
v1.5.1
v1.5.10
v1.5.11
v1.5.12
v1.5.13
v1.5.14
v1.5.15
v1.5.16
v1.5.17
v1.5.18
v1.5.19
v1.5.2
v1.5.20
v1.5.21
v1.5.22
v1.5.23
v1.5.24
v1.5.25
v1.5.26
v1.5.27
v1.5.3
v1.5.4
v1.5.5
v1.5.6
v1.5.7
v1.5.8
v1.5.9
v1.6.0
v1.6.1
v1.6.2
v1.6.3
v1.6.4
v1.7.0
v1.7.2
v1.7.3
v1.7.4
v1.7.5

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-16318.json"