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CVE-2026-11941— Use-after-free in connection ID iterator and FFI functions

Quick assessment

Affected
Cloudflare Quiche
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.

Cloudflare quiche是美国Cloudflare公司开源的一个 IETF 指定的 QUIC 传输协议和 HTTP/3 的实现。 Cloudflare Quiche 0.20.0版本至0.29.1版本存在资源管理错误漏洞，该漏洞源于连接ID迭代器FFI函数中存在2个释放后重用漏洞，可能导致未修补的应用程序引用已释放的内存，从而导致进程崩溃（拒绝服务）。

CVSS 5.6 · Medium EPSS 0.25% · P17

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution

Affected Version Matrix 1

VendorProduct Version RangeStatus
Cloudflare Quiche 0.20.0≤ 0.29.1 affected
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I. Basic Information for CVE-2026-11941

Vulnerability Information
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Vulnerability Title
Use-after-free in connection ID iterator and FFI functions
Source: CVE Program / CVE List V5
Vulnerability Description
Cloudflare Quiche was affected by 2 use-after-free vulnerabilities in the connection ID iterator FFI functions. The “quiche_connection_id_iter_next” and “quiche_conn_retired_scid_next” functions would return a pointer to a “ConnectionId” to the applications via function arguments, but the owned “ConnectionId” would be dropped at the end of those functions' scope. Only applications using those FFI functions are affected. The FFI API is disabled by default by a build-time feature flag. Impact If unpatched, an application calling the affected FFI functions will dereference freed memory. The most likely outcome is undefined behavior leading to a process crash (denial of service). Depending on allocator state, the read may also return adjacent heap contents, resulting in limited information disclosure or incorrect connection identifier handling. Mitigation Users are requested to upgrade to quiche 0.29.2 which is the earliest version containing the fix for this issue.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
释放后使用
Source: CVE Program / CVE List V5
Vulnerability Title
Cloudflare Quiche 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Cloudflare quiche是美国Cloudflare公司开源的一个 IETF 指定的 QUIC 传输协议和 HTTP/3 的实现。 Cloudflare Quiche 0.20.0版本至0.29.1版本存在资源管理错误漏洞，该漏洞源于连接ID迭代器FFI函数中存在2个释放后重用漏洞，可能导致未修补的应用程序引用已释放的内存，从而导致进程崩溃（拒绝服务）。
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
Cloudflare Quiche 0.20.0 ~ 0.29.1 -

II. Public POCs for CVE-2026-11941

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III. Intelligence Information for CVE-2026-11941

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Vendor Advisories for CVE-2026-11941 (1)

IV. Related Vulnerabilities

Same product: Quiche
Same vendor: Cloudflare
Same weakness: CWE-416

V. Comments for CVE-2026-11941

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