CVE-2019-9901: Github.com/envoyproxy/envoy EnvoyProxy Envoy Missing HTTP URL Vulnerability

CRITICAL
Advisory Identifier: GHSA-2wmf-p7f8-w42h
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CVSS 10.0
CWE-706
Published
Advisory Summary

CVE-2019-9901 is a CRITICAL (CVSS 10.0) envoyproxy envoy missing http url vulnerability (CWE-706: Use of Incorrectly-Resolved Name or Reference) affecting Github.com/envoyproxy/envoy libraries in the Go ecosystem. The issue involves envoyproxy envoy missing http url path normalization. Remediation is available by upgrading affected packages to version 1.9.1.

CVE-2019-9901 at a Glance

CVE Identifier CVE-2019-9901
GHSA Identifier GHSA-2wmf-p7f8-w42h
Severity CRITICAL
CVSS v3.1 Base Score 10.0
CWE Classification CWE-706: Use of Incorrectly-Resolved Name or Reference
Affected Product Github.com/envoyproxy/envoy
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 10.0

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2019-9901

To remediate this vulnerability, upgrade all affected Github.com/envoyproxy/envoy dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/envoyproxy/envoy fixed: 1.9.1 
Upgrade github.com/envoyproxy/envoy to 1.9.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/envoyproxy/envoy

How to Check if You Are Affected

To determine whether your application is affected by CVE-2019-9901, inspect your project dependencies for Github.com/envoyproxy/envoy:

inspect dependencies for github.com/envoyproxy/envoy

Analyze the terminal output to locate any version of Github.com/envoyproxy/envoy in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.9.1), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-706: Use of Incorrectly-Resolved Name or Reference, where the product uses a name or reference to access a resource, but the name/reference resolves to a resource that is outside of the intended control sphere. In Github.com/envoyproxy/envoy, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2019-9901 Affected Github.com/envoyproxy/envoy Versions

1 component(s)
Fixed Versions:
1.9.1
Product / Package Ecosystem Affected Versions Fixed Version
github.com/envoyproxy/envoy
golang/github.com/envoyproxy/envoy
Go
< 1.9.1
1.9.1

References

www.envoyproxy.io/docs/envoy/v1.9.1/i... WEB
https://www.envoyproxy.io/docs/envoy/v1.9.1/intro/version_history
GitHub Advisory / Wiki ADVISORY
https://github.com/envoyproxy/envoy/security/advisories/GHSA-xcx5-93pw-jw2w
NVD — CVE-2019-9901 NVD
https://nvd.nist.gov/vuln/detail/CVE-2019-9901
Github.com/envoyproxy/envoy Source Repository REPOSITORY
https://github.com/envoyproxy/envoy/issues/6435
Security Fix Commit FIX COMMIT
https://github.com/envoyproxy/envoy/commit/e668e669677e52a00d99652b5a260d1cedafdfa8
Github.com/envoyproxy/envoy Source Repository REPOSITORY
https://github.com/envoyproxy/envoy
Github.com/envoyproxy/envoy Source Repository REPOSITORY
https://github.com/envoyproxy/envoy/blob/main/security/postmortems/cve-2019-9900.md
groups.google.com/forum/ WEB
https://groups.google.com/forum/#!topic/envoy-announce/VoHfnDqZiAM

Frequently Asked Questions

What is CVE-2019-9901?
CVE-2019-9901 is a security vulnerability in Github.com/envoyproxy/envoy involving EnvoyProxy Envoy Missing HTTP URL path normalization under CWE-706: Use of Incorrectly-Resolved Name or Reference.
Which Github.com/envoyproxy/envoy versions are affected?
Affected versions include releases prior to 1.9.1 across affected packages: github.com/envoyproxy/envoy.
What version fixes CVE-2019-9901?
Upgrading to 1.9.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/envoyproxy/envoy affected?
Yes, github.com/envoyproxy/envoy is affected in releases prior to 1.9.1. Upgrade your dependency to 1.9.1 or later.
What is the CVSS score of CVE-2019-9901?
CVE-2019-9901 has a CVSS v3.1 base score of 10.0 (CRITICAL) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2019-9901?
CVE-2019-9901 is classified under CWE-706: Use of Incorrectly-Resolved Name or Reference (The product uses a name or reference to access a resource, but the name/reference resolves to a resource that is outside of the intended control sphere.).
How can I check Go dependencies for CVE-2019-9901?
Run the dependency tree command: 'inspect dependencies for github.com/envoyproxy/envoy'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2wmf-p7f8-w42h",
  "modified" : "2023-08-24T13:07:21Z",
  "published" : "2022-05-24T16:44:38Z",
  "aliases" : [ "CVE-2019-9901" ],
  "summary" : "EnvoyProxy Envoy Missing HTTP URL path normalization",
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/envoyproxy/envoy"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.9.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.9.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/envoyproxy/envoy/security/advisories/GHSA-xcx5-93pw-jw2w"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2019-9901"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/envoyproxy/envoy/issues/6435"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/envoyproxy/envoy/commit/e668e669677e52a00d99652b5a260d1cedafdfa8"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/envoyproxy/envoy"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/envoyproxy/envoy/blob/main/security/postmortems/cve-2019-9900.md"
  }, {
    "type" : "WEB",
    "url" : "https://groups.google.com/forum/#!topic/envoy-announce/VoHfnDqZiAM"
  }, {
    "type" : "WEB",
    "url" : "https://www.envoyproxy.io/docs/envoy/v1.9.1/intro/version_history"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-706" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-07-14T20:27:42Z",
    "nvd_published_at" : "2019-04-25T16:29:00Z"
  }
}