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CVE-2026-16318— QUIC Transport Parameters Memory Leak During HelloRetryRequest in s2n-tls

Quick assessment

Affected
Amazon s2n-tls
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Amazon s2n-tls是美国Amazon公司开源的一款TLS协议实现库。 Amazon s2n-tls v1.7.5及之前版本存在资源管理错误漏洞，该漏洞源于QUIC传输参数扩展处理程序错误使用s2n_alloc代替s2n_realloc存储对等体传输参数，导致内存泄漏，可能被未认证用户利用，通过强制HelloRetryRequests造成每次握手约64 KB不可达内存，长期运行服务器进程内存消耗增加。

CVSS 5.3 · Medium EPSS 0.53% · P43

Possible ATT&CK Techniques 1 AI

T1496 · Resource Hijacking

Affected Version Matrix 1

VendorProduct Version RangeStatus
Amazon s2n-tls ≤ v1.7.5 affected
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I. Basic Information for CVE-2026-16318

Vulnerability Information
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Vulnerability Title
QUIC Transport Parameters Memory Leak During HelloRetryRequest in s2n-tls
Source: CVE Program / CVE List V5
Vulnerability Description
The QUIC transport parameters extension handler in s2n-tls incorrectly uses s2n_alloc instead of s2n_realloc 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
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
在移除最后引用时对内存的释放不恰当(内存泄露)
Source: CVE Program / CVE List V5
Vulnerability Title
Amazon s2n-tls 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Amazon s2n-tls是美国Amazon公司开源的一款TLS协议实现库。 Amazon s2n-tls v1.7.5及之前版本存在资源管理错误漏洞，该漏洞源于QUIC传输参数扩展处理程序错误使用s2n_alloc代替s2n_realloc存储对等体传输参数，导致内存泄漏，可能被未认证用户利用，通过强制HelloRetryRequests造成每次握手约64 KB不可达内存，长期运行服务器进程内存消耗增加。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Amazon s2n-tls 0 ~ v1.7.5 -

II. Public POCs for CVE-2026-16318

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III. Intelligence Information for CVE-2026-16318

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Vendor Advisories for CVE-2026-16318 (2)

IV. Related Vulnerabilities

Same product: s2n-tls
Same vendor: Amazon
Same weakness: CWE-401

V. Comments for CVE-2026-16318

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