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CVE-2021-43826— Crash when tunneling TCP over HTTP in Envoy

Quick assessment

Affected
envoyproxy envoy
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.

Envoy是一款开源的分布式代理服务器。 Envoy 存在资源管理错误漏洞，该漏洞源于当为上游隧道配置envoy_v3_api_field_extensions.filters.network.tcp_proxy.v3.TcpProxy.tunneling_config时发生崩溃，并且下游连接断开，而上游连接或 http/2 流仍然存在。 没有解决此问题的方法。 建议用户升级。

CVSS 7.5 · High EPSS 1.06% · P63

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service
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I. Basic Information for CVE-2021-43826

Vulnerability Information
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Vulnerability Title
Crash when tunneling TCP over HTTP in Envoy
Source: CVE Program / CVE List V5
Vulnerability Description
Envoy is an open source edge and service proxy, designed for cloud-native applications. In affected versions of Envoy a crash occurs when configured for :ref:`upstream tunneling <envoy_v3_api_field_extensions.filters.network.tcp_proxy.v3.TcpProxy.tunneling_config>` and the downstream connection disconnects while the the upstream connection or http/2 stream is still being established. There are no workarounds for this issue. Users are advised to upgrade.
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:H
Source: CVE Program / CVE List V5
Vulnerability Type
释放后使用
Source: CVE Program / CVE List V5
Vulnerability Title
Envoy 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Envoy是一款开源的分布式代理服务器。 Envoy 存在资源管理错误漏洞，该漏洞源于当为上游隧道配置envoy_v3_api_field_extensions.filters.network.tcp_proxy.v3.TcpProxy.tunneling_config时发生崩溃，并且下游连接断开，而上游连接或 http/2 流仍然存在。 没有解决此问题的方法。 建议用户升级。
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
envoyproxy envoy < 1.18.6 -

II. Public POCs for CVE-2021-43826

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III. Intelligence Information for CVE-2021-43826

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Patches & Fixes for CVE-2021-43826 (1)

Vendor Advisories for CVE-2021-43826 (1)

Same Patch Batch · envoyproxy · 2022-02-22 · 8 CVEs total

CVE-2022-21655 7.5 HIGH Incorrect handling of internal redirects results in crash in Envoy
CVE-2021-43824 7.5 HIGH Null pointer dereference in envoy
CVE-2022-21654 7.4 HIGH Incorrect configuration handling allows TLS session re-use without re-validation in Envoy
CVE-2022-21656 7.4 HIGH X.509 subjectAltName matching bypass in Envoy
CVE-2022-21657 6.8 MEDIUM X.509 Extended Key Usage and Trust Purposes bypass in Envoy
CVE-2021-43825 6.1 MEDIUM Use-after-free in Envoy
CVE-2022-23606 4.4 MEDIUM Crash when a cluster is deleted in Envoy

IV. Related Vulnerabilities

Same product: envoy
Same vendor: envoyproxy
Same weakness: CWE-416

V. Comments for CVE-2021-43826

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