CVE-2026-73551

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.

CVSS 3.1

5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS

0.5% chance of exploitation in the next 30 days; higher than 44% of CVEs (scores of 2026-10-25)

CWE

CWE-647

Published

2026-09-21

Modified

2026-10-05

Record from

the NVD, synced 2026-10-19

Affected

• envoyproxy:envoy

References

• https://github.com/envoyproxy/envoy/commit/28b6d60a6d96edeece121cac5be701eb46cc7f24
• https://github.com/envoyproxy/envoy/commit/d40a68b0a30a003c4e0a9fd3af637f828b52c37b
• https://github.com/envoyproxy/envoy/commit/e9d6c329f9a3ff19432bf39b60c601df7e3eda33
• https://github.com/envoyproxy/envoy/commit/f74d1107c4f5c9679b66f7a03a6c5b75ddde1989
• https://github.com/envoyproxy/envoy/releases/tag/v1.36.10

Check your stackJSON