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Fencer Vulns
medium 6.5

CVE-2019-9901 json

EnvoyProxy Envoy Missing HTTP URL path normalization

published 2019-04-25 7 y ago modified 2026-09-10 1 mo ago also GHSA-2wmf-p7f8-w42h , GHSA-xcx5-93pw-jw2w , EUVD-2022-2065

cvss
6.5
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
5.0%
EPSS 5.0% chance of exploitation in 30 days, percentile 92%
public exploits
0
none known

Summary

Envoy 1.9.0 and before does not normalize HTTP URL paths. A remote attacker may craft a relative path, e.g., something/../admin, to bypass access control, e.g., a block on /admin. A backend server could then interpret the non-normalized path and provide an attacker access beyond the scope provided for by the access control policy.

Patch / fix

  • go github.com/envoyproxy/envoy 1.9.1
  • servicemesh-proxy service mesh 0 0.9.1-1.el7

red hat advisories RHSA-2019:0741

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-9901 updated cvss 8.3

istio/envoy: Path traversal via URL Patch manipulation in HTTP/1.x header

  • Red Hat OpenShift Service Mesh 0 Tech Preview servicemesh-proxy 0.9.1-1.el7
    fixed: vendor fix RHSA-2019:0741

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.95% chance of exploitation in the next 30 days, higher than 92% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.0 6.5 CVSS:3.0/AC:H/AV:N/A:L/C:L/I:L/PR:N/S:C/UI:N
CNA 3.0 6.5 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:L
NVD 3.0 10.0 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.0 10.0 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/envoyproxy/envoy
<1.9.1
1.9.1

Classification

Weakness
  • CWE-706 Use of Incorrectly-Resolved Name or Reference

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.