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CVE-2026-73547— Envoy ext_authz: request `:path` pseudoheader dereferenced w/o null check

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 是一款专为云原生应用设计的开源边缘代理和服务代理。在 1.36.10、1.37.6、1.38.4 和 1.39.1 版本之前，Envoy 的 ext_authz（外部授权）过滤器在应用授权响应中的或时，假定请求中包含伪头部。然而，对于无路径的 CONNECT 请求，会返回空指针（null），而在解析查询字符串时会解引用该空指针，从而导致崩溃。未认证的下游客户端若在此场景下触发查询参数修改操作，即可使 Envoy 进程崩溃。该漏洞的触发前提是：部署环境必须允许无路径的 CONNECT 请求，并配

CVSS 7.5 · High EPSS 0.55% · P46 Updated Sep 23, 2026

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 4

Vendor	Product	Version Range	Status
envoyproxy	envoy	`< 1.36.10`	affected
		`>= 1.37.0, < 1.37.6`	affected
		`>= 1.38.0, < 1.38.4`	affected
		`>= 1.39.0, < 1.39.1`	affected

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Vulnerability Information

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Vulnerability Title

Envoy ext_authz: request `:path` pseudoheader dereferenced w/o null check

Source: CVE Program / CVE List V5

Vulnerability Description

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy's ext_authz filter assumes that a request contains a :path pseudoheader when applying query_parameters_to_set or query_parameters_to_remove from an authorization response. A path-less CONNECT request makes request_headers_->Path() return null, and Filter::onComplete dereferences that pointer while parsing the query string. An unauthenticated downstream client can crash the Envoy process when the filter and authorization response use query-parameter mutation. The relevant scope boundary is that the deployment must accept path-less CONNECT and configure ext_authz query-parameter mutation. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

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

输入验证不恰当

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
envoyproxy	envoy	< 1.36.10	-

II. Public POCs for CVE-2026-73547

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III. Intelligence Information for CVE-2026-73547

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Patches & Fixes for CVE-2026-73547 (4)

Other References for CVE-2026-73547 (5)

🔗 Release v1.38.4 · envoyproxy/envoy · GitHub Read full article x_refsource_MISC
🔗 Release v1.37.6 · envoyproxy/envoy · GitHub Read full article x_refsource_MISC
🔗 Release v1.39.1 · envoyproxy/envoy · GitHub Read full article x_refsource_MISC
🔗 Release v1.36.10 · envoyproxy/envoy · GitHub Read full article x_refsource_MISC
🔗 ext_authz: request `:path` pseudoheader dereferenced w/o null check · Advisory · envoyproxy/envoy · GitHub Read full article x_refsource_CONFIRM

https://www.cve.org/CVERecord?id=CVE-2026-73547

Same Patch Batch · envoyproxy · 2026-09-21 · 13 CVEs total

CVE-2026-73550	7.5 HIGH	Envoy: HTTP/2 Discarded Host Header 200 GB Header-Copy OOM in Envoy
CVE-2026-73512	7.5 HIGH	Envoy: use-after-free in QUIC on internal redirects
CVE-2026-73553	7.5 HIGH	Envoy: RBAC Authorization Bypass via Path Parameters
CVE-2026-73513	7.5 HIGH	Envoy: oghttp2 upstream trailers incorrect handling
CVE-2026-73548	7.5 HIGH	Envoy: Cross-user response poisoning via a generic (non-WebSocket) HTTP upgrade on Envoy's
CVE-2026-73552	7.5 HIGH	Envoy: HTTP RBAC safe_regex can fail open on RFC-valid obs-text header values
CVE-2026-73546	7.4 HIGH	Envoy: Stored XSS in Admin Stats Interface (/stats?format=html)
CVE-2026-48521	5.9 MEDIUM	Envoy: HTTP/3 connection pool selection null-derefs in ProdClusterManagerFactory::allocate
CVE-2026-50572	5.9 MEDIUM	Envoy: ext_authz - RawHttpClientImpl onSuccess 0x0 segfault
CVE-2026-73511	5.3 MEDIUM	Envoy: Potential path-matching/authentication bypass when using Envoy in combination with
CVE-2026-73549	5.3 MEDIUM	Envoy - Incomplete fix for CVE-2026-26310: copyInternetAddressAndPort crashes on scoped IP
CVE-2026-73551	5.3 MEDIUM	Envoy: Path normalization does not handle dot and dotdot segments with parameters

IV. Related Vulnerabilities

Same product: envoy

Same vendor: envoyproxy

Same weakness: CWE-20