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CVE-2026-73547

Envoyproxy Envoy NULL pointer dereference

7.5 HIGHPublic exploitEPSS 0.55%
  1. Published21 Sept 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Envoyproxy Envoy≥ 1.37.0 < 1.37.6 · ≥ 1.38.0 < 1.38.4 · ≥ 1.39.0 < 1.39.1 · < 1.36.10

Remediation

Fixed in
Envoyproxy Envoy≥ 1.37.6

References

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Frequently asked

Is CVE-2026-73547 being actively exploited?

CVE-2026-73547 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.55%.

How severe is CVE-2026-73547?

CVE-2026-73547 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.55% probability of exploitation.

Which products are affected by CVE-2026-73547?

Affected products include Envoyproxy Envoy.

How do I fix CVE-2026-73547?

Upgrade affected software to a fixed version, for example Envoyproxy Envoy 1.37.6 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-73547 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.