CVE-2018-16886: Go.etcd.io/etcd/v3 Authentication Bypass Vulnerability

HIGH
Advisory Identifier: GHSA-h6xx-pmxh-3wgp
Share
CVSS 8.1
CWE-287 CWE-285
Published
Advisory Summary

CVE-2018-16886 is a HIGH (CVSS 8.1) authentication bypass vulnerability (CWE-287: Improper Authentication) affecting Go.etcd.io/etcd/v3 libraries in the Go ecosystem. The issue involves go.etcd.io/etcd authentication bypass. Remediation is available by upgrading affected packages to version 3.2.26, 3.3.11, 0.5.0-alpha.5.0.20190108173120-83c051b701d3.

CVE-2018-16886 at a Glance

CVE Identifier CVE-2018-16886
GHSA Identifier GHSA-h6xx-pmxh-3wgp
Severity HIGH
CVSS v3.1 Base Score 8.1
CWE Classification CWE-287: Improper Authentication
Affected Product Go.etcd.io/etcd/v3
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 8.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).

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

How to Fix CVE-2018-16886

To remediate this vulnerability, upgrade all affected Go.etcd.io/etcd/v3 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

go.etcd.io/etcd/v3 fixed: 3.2.26 
Upgrade go.etcd.io/etcd/v3 to 3.2.26
go.etcd.io/etcd/v3 fixed: 3.3.11 
Upgrade go.etcd.io/etcd/v3 to 3.3.11
go.etcd.io/etcd fixed: 0.5.0-alpha.5.0.20190108173120-83c051b701d3 
Upgrade go.etcd.io/etcd to 0.5.0-alpha.5.0.20190108173120-83c051b701d3
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 go.etcd.io/etcd/v3

How to Check if You Are Affected

To determine whether your application is affected by CVE-2018-16886, inspect your project dependencies for Go.etcd.io/etcd/v3:

inspect dependencies for go.etcd.io/etcd/v3

Analyze the terminal output to locate any version of Go.etcd.io/etcd/v3 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.2.26), 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-287: Improper Authentication, where when an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. In Go.etcd.io/etcd/v3, 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

etcd versions 3.2.x before 3.2.26 and 3.3.x before 3.3.11 are vulnerable to an improper authentication issue when role-based access control (RBAC) is used and client-cert-auth is enabled. If an etcd client server TLS certificate contains a Common Name (CN) which matches a valid RBAC username, a remote attacker may authenticate as that user with any valid (trusted) client certificate in a REST API request to the gRPC-gateway.

CVE-2018-16886 Affected Go.etcd.io/etcd/v3 Versions

3 component(s)
Fixed Versions:
3.2.263.3.110.5.0-alpha.5.0.20190108173120-83c051b701d3
Product / Package Ecosystem Affected Versions Fixed Version
go.etcd.io/etcd/v3
golang/go.etcd.io/etcd/v3
Go
≥ 3.2.0
< 3.2.26
3.2.26
go.etcd.io/etcd/v3
golang/go.etcd.io/etcd/v3
Go
≥ 3.3.0
< 3.3.11
3.3.11
go.etcd.io/etcd
golang/go.etcd.io/etcd
Go
< 0.5.0-alpha.5.0.20190108173120-83c051b701d3
0.5.0-alpha.5.0.20190108173120-83c051b701d3

References

NVD — CVE-2018-16886 NVD
https://nvd.nist.gov/vuln/detail/CVE-2018-16886
Go.etcd.io/etcd/v3 Source Repository REPOSITORY
https://github.com/etcd-io/etcd/pull/10366
Security Fix Commit FIX COMMIT
https://github.com/etcd-io/etcd/commit/0191509637546621d6f2e18e074e955ab8ef374d
Security Fix Commit FIX COMMIT
https://github.com/etcd-io/etcd/commit/bf9d0d8291dc71ecbfb2690612954e1a298154b2
access.redhat.com/errata/rhsa-2019:02... WEB
https://access.redhat.com/errata/RHSA-2019:0237
access.redhat.com/errata/rhsa-2019:13... WEB
https://access.redhat.com/errata/RHSA-2019:1352
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16886
Go.etcd.io/etcd/v3 Source Repository REPOSITORY
https://github.com/etcd-io/etcd
Go.etcd.io/etcd/v3 Source Repository REPOSITORY
https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.2.md#security-authentication
Go.etcd.io/etcd/v3 Source Repository REPOSITORY
https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.3.md#security-authentication
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JX7QTIT465BQGRGNCE74RATRQLKT2QE4
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UPGYHMSKDPW5GAMI7BEP3XQRVRLLBJKS
pkg.go.dev/vuln/go-2021-0077 WEB
https://pkg.go.dev/vuln/GO-2021-0077
Go.etcd.io/etcd/v3 Security Information SECURITY
http://www.securityfocus.com/bid/106540

Frequently Asked Questions

What is CVE-2018-16886?
CVE-2018-16886 is a security vulnerability in Go.etcd.io/etcd/v3 involving go.etcd.io/etcd Authentication Bypass under CWE-287: Improper Authentication.
Which Go.etcd.io/etcd/v3 versions are affected?
Affected versions include releases prior to 3.2.26, 3.3.11, 0.5.0-alpha.5.0.20190108173120-83c051b701d3 across affected packages: go.etcd.io/etcd/v3, go.etcd.io/etcd.
What version fixes CVE-2018-16886?
Upgrading to 3.2.26, 3.3.11, 0.5.0-alpha.5.0.20190108173120-83c051b701d3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is go.etcd.io/etcd/v3 affected?
Yes, go.etcd.io/etcd/v3 is affected in releases prior to 3.2.26, 3.3.11. Upgrade your dependency to 3.2.26, 3.3.11 or later.
Is go.etcd.io/etcd affected?
Yes, go.etcd.io/etcd is affected in releases prior to 0.5.0-alpha.5.0.20190108173120-83c051b701d3. Upgrade your dependency to 0.5.0-alpha.5.0.20190108173120-83c051b701d3 or later.
What is the CVSS score of CVE-2018-16886?
CVE-2018-16886 has a CVSS v3.1 base score of 8.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2018-16886?
CVE-2018-16886 is classified under CWE-287: Improper Authentication (When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.).
How can I check Go dependencies for CVE-2018-16886?
Run the dependency tree command: 'inspect dependencies for go.etcd.io/etcd/v3'. 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-h6xx-pmxh-3wgp",
  "modified" : "2023-08-30T11:13:45Z",
  "published" : "2022-04-12T22:41:32Z",
  "aliases" : [ "CVE-2018-16886" ],
  "summary" : "go.etcd.io/etcd Authentication Bypass",
  "details" : "etcd versions 3.2.x before 3.2.26 and 3.3.x before 3.3.11 are vulnerable to an improper authentication issue when role-based access control (RBAC) is used and client-cert-auth is enabled. If an etcd client server TLS certificate contains a Common Name (CN) which matches a valid RBAC username, a remote attacker may authenticate as that user with any valid (trusted) client certificate in a REST API request to the gRPC-gateway.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "go.etcd.io/etcd/v3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.2.0"
      }, {
        "fixed" : "3.2.26"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "go.etcd.io/etcd/v3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.3.0"
      }, {
        "fixed" : "3.3.11"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "go.etcd.io/etcd"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.5.0-alpha.5.0.20190108173120-83c051b701d3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2018-16886"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/pull/10366"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/commit/0191509637546621d6f2e18e074e955ab8ef374d"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/commit/bf9d0d8291dc71ecbfb2690612954e1a298154b2"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2019:0237"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2019:1352"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16886"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/etcd-io/etcd"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.2.md#security-authentication"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.3.md#security-authentication"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JX7QTIT465BQGRGNCE74RATRQLKT2QE4"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UPGYHMSKDPW5GAMI7BEP3XQRVRLLBJKS"
  }, {
    "type" : "WEB",
    "url" : "https://pkg.go.dev/vuln/GO-2021-0077"
  }, {
    "type" : "WEB",
    "url" : "http://www.securityfocus.com/bid/106540"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-285", "CWE-287" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-05-19T21:49:34Z",
    "nvd_published_at" : null
  }
}