Medium severity · published Sep 21, 2026
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)
5.3
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EN
envoy · envoyproxy
< 1.36.10; >= 1.37.0, < 1.37.6; >= 1.38.0, < 1.38.4; >= 1.39.0, < 1.39.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-73511
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-73511
Patch
https://github.com/envoyproxy/envoy/commit/26d5
Patch
https://github.com/envoyproxy/envoy/commit/50f7bfa48dccfee339822e9846b2b8053e07d325
Patch
https://github.com/envoyproxy/envoy/commit/b205d1f4982e14ce5693ba94ef84d37e7155e050
Patch
https://github.com/envoyproxy/envoy/commit/fcb663752c7055257f5dcc8b6ce6c7c905ebb1ff
Release Notes
https://github.com/envoyproxy/envoy/releases/tag/v1.36.10
Release Notes
https://github.com/envoyproxy/envoy/releases/tag/v1.37.6
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