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OpenAdvisories
Medium · 5.3 CVE-2026-73551 EUVD-2026-84119

Envoy: Path normalization does not handle dot and dotdot segments with parameters

Published Sep 21, 2026 · Updated Sep 28, 2026 · Assigned by GitHub_M

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 URL normalization does not recognize dot and dotdot path segments when they carry semicolon parameters. A request such as /user/..;foo=bar/admin is therefore not canonicalized to /admin even when path normalization is enabled. If an upstream interprets the segment according to RFC 3986 while Envoy applies routing or RBAC to the uncollapsed path, a remote client can cause path confusion and bypass path-based security policy. The relevant scope boundary is that the security consequence depends on a downstream/upstream path interpretation mismatch or a path-based Envoy decision. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

Affected products

VendorProductAffectedFixed
envoyproxy envoy < 1.36.10, >= 1.37.0, < 1.37.6, >= 1.38.0, < 1.38.4, >= 1.39.0, < 1.39.1 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
openSUSE Tumbleweed istioctl 1.30.4-1.1 openSUSE-SU-2026:11630-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2023 ecs-service-connect-agent v1.39.1.0-1.amzn2023 ALAS2023-2026-2149

Advisories 2

References