CVE-2026-73511

Envoy: Potential path-matching/authentication bypass when using Envoy in combination with a backend stripping per-segment path (matrix) parameters (e.g. Apache Tomcat)

MEDIUM
5.3
CVSS Score
Published: September 21, 2026 at 08:20 PM UTC
Updated: October 5, 2026 at 02:35 PM UTC
1 product affected across 1 vendorEnvoy

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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 normally matches the raw request path, while servlet backends such as Apache Tomcat strip semicolon matrix parameters from each path segment before resolving the resource. Envoy's ignore_path_parameters_in_path_matching option instead truncates at the first semicolon and still does not match per-segment backend behavior. A remote client can use a parameterized protected segment, or a parameter on an earlier segment, to make Envoy select an unprotected fallback while the backend resolves the protected resource. The relevant scope boundary is that the bypass requires both a path-based Envoy decision and a backend that strips semicolon parameters per segment. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.36.10v < 1.37.6v < 1.38.4v < 1.39.11.37.0 ≤ v < 1.37.61.38.0 ≤ v < 1.38.41.39.0 ≤ v < 1.39.1
Affected range stops below 1.36.10, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.37.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.38.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.39.1, so it looks safe — our inference, not a vendor statement

References (9)

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-289CWE-436

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