Envoy Proxy up to 1.36.9/1.37.5/1.38.3/1.39.0 ext_authz filter Filter::onComplete input validation

Summaryinfo

A vulnerability has been found in Envoy Proxy Envoy up to 1.36.9/1.37.5/1.38.3/1.39.0 and classified as problematic. Affected by this vulnerability is the function Filter::onComplete of the component ext_authz filter. Performing a manipulation results in input validation. This vulnerability was named CVE-2026-73547. The attack may be initiated remotely. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Envoy Proxy Envoy up to 1.36.9/1.37.5/1.38.3/1.39.0. This affects the function Filter::onComplete of the component ext_authz filter. The manipulation with an unknown input leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-73547 since 08/12/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 1.36.10, 1.37.6, 1.38.4 or 1.39.1 eliminates this vulnerability.

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Productinfo

Type

• Firewall Software

Vendor

• Envoy Proxy

Name

• Envoy

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24
• 1.25
• 1.26
• 1.27
• 1.28
• 1.29
• 1.30
• 1.31
• 1.32
• 1.33
• 1.34
• 1.35
• 1.36
• 1.36.0
• 1.36.1
• 1.36.2
• 1.36.3
• 1.36.4
• 1.36.5
• 1.36.6
• 1.36.7
• 1.36.8
• 1.36.9
• 1.37
• 1.37.0
• 1.37.1
• 1.37.2
• 1.37.3
• 1.37.4
• 1.37.5
• 1.38
• 1.38.0
• 1.38.1
• 1.38.2
• 1.38.3
• 1.39.0

License

• free

CPE 2.3info

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CPE 2.2info

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