CVE-2020-26290: Github.com/dexidp/dex Critical Security Issues Vulnerability

CRITICAL
Advisory Identifier: GHSA-m9hp-7r99-94h5
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CVSS 9.3
CWE-347
Published
Advisory Summary

CVE-2020-26290 is a CRITICAL (CVSS 9.3) critical security issues vulnerability (CWE-347: Improper Verification of Cryptographic Signature) affecting Github.com/dexidp/dex libraries in the Go ecosystem. The issue involves critical security issues in xml encoding in github.com/dexidp/dex. Remediation is available by upgrading affected packages to version 2.27.0, 1.1.0.

CVE-2020-26290 at a Glance

CVE Identifier CVE-2020-26290
GHSA Identifier GHSA-m9hp-7r99-94h5
Severity CRITICAL
CVSS v3.1 Base Score 9.3
CWE Classification CWE-347: Improper Verification of Cryptographic Signature
Affected Product Github.com/dexidp/dex
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 9.3

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

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

How to Fix CVE-2020-26290

To remediate this vulnerability, upgrade all affected Github.com/dexidp/dex 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/dexidp/dex fixed: 2.27.0 
Upgrade github.com/dexidp/dex to 2.27.0
github.com/russellhaering/goxmldsig fixed: 1.1.0 
Upgrade github.com/russellhaering/goxmldsig to 1.1.0
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/dexidp/dex

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-26290, inspect your project dependencies for Github.com/dexidp/dex:

inspect dependencies for github.com/dexidp/dex

Analyze the terminal output to locate any version of Github.com/dexidp/dex in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.27.0), 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-347: Improper Verification of Cryptographic Signature, where the product does not verify, or incorrectly verifies, the cryptographic signature for data. In Github.com/dexidp/dex, 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

### Impact The following vulnerabilities have been disclosed, which impact users leveraging the SAML connector: Signature Validation Bypass (CVE-2020-15216): https://github.com/russellhaering/goxmldsig/security/advisories/GHSA-q547-gmf8-8jr7 `encoding/xml` instabilities: - [Element namespace prefix instability (CVE-2020-29511)](https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-elements.md) - [Attribute namespace prefix instability (CVE-2020-29509)](https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-attributes.md) - [Directive comment instability (CVE-2020-29510)](https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-directives.md) ### Patches Immediately update to [Dex v2.27.0](https://github.com/dexidp/dex/releases/tag/v2.27.0). ### Workarounds There are no known workarounds.

CVE-2020-26290 Affected Github.com/dexidp/dex Versions

2 component(s)
Fixed Versions:
2.27.01.1.0
Product / Package Ecosystem Affected Versions Fixed Version
github.com/dexidp/dex
golang/github.com/dexidp/dex
Go
< 2.27.0
2.27.0
github.com/russellhaering/goxmldsig
golang/github.com/russellhaering/goxmldsig
Go
< 1.1.0
1.1.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/dexidp/dex/security/advisories/GHSA-m9hp-7r99-94h5
GitHub Advisory / Wiki ADVISORY
https://github.com/russellhaering/goxmldsig/security/advisories/GHSA-q547-gmf8-8jr7
NVD — CVE-2020-26290 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-26290
Security Fix Commit FIX COMMIT
https://github.com/dexidp/dex/commit/324b1c886b407594196113a3dbddebe38eecd4e8
Security Fix Commit FIX COMMIT
https://github.com/russellhaering/goxmldsig/commit/f6188febf0c29d7ffe26a0436212b19cb9615e64
Github.com/dexidp/dex Release RELEASE
https://github.com/dexidp/dex/releases/tag/v2.27.0
GitHub Advisory / Wiki ADVISORY
https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-attributes.md
GitHub Advisory / Wiki ADVISORY
https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-directives.md
GitHub Advisory / Wiki ADVISORY
https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-elements.md
mattermost.com/blog/coordinated-di... WEB
https://mattermost.com/blog/coordinated-disclosure-go-xml-vulnerabilities
pkg.go.dev/vuln/go-2020-0050 WEB
https://pkg.go.dev/vuln/GO-2020-0050

Frequently Asked Questions

What is CVE-2020-26290?
CVE-2020-26290 is a security vulnerability in Github.com/dexidp/dex involving Critical security issues in XML encoding in github.com/dexidp/dex under CWE-347: Improper Verification of Cryptographic Signature.
Which Github.com/dexidp/dex versions are affected?
Affected versions include releases prior to 2.27.0, 1.1.0 across affected packages: github.com/dexidp/dex, github.com/russellhaering/goxmldsig.
What version fixes CVE-2020-26290?
Upgrading to 2.27.0, 1.1.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/dexidp/dex affected?
Yes, github.com/dexidp/dex is affected in releases prior to 2.27.0. Upgrade your dependency to 2.27.0 or later.
Is github.com/russellhaering/goxmldsig affected?
Yes, github.com/russellhaering/goxmldsig is affected in releases prior to 1.1.0. Upgrade your dependency to 1.1.0 or later.
What is the CVSS score of CVE-2020-26290?
CVE-2020-26290 has a CVSS v3.1 base score of 9.3 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N.
What CWE is associated with CVE-2020-26290?
CVE-2020-26290 is classified under CWE-347: Improper Verification of Cryptographic Signature (The product does not verify, or incorrectly verifies, the cryptographic signature for data.).
How can I check Go dependencies for CVE-2020-26290?
Run the dependency tree command: 'inspect dependencies for github.com/dexidp/dex'. 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-m9hp-7r99-94h5",
  "modified" : "2021-05-21T20:49:36Z",
  "published" : "2021-12-20T17:53:53Z",
  "aliases" : [ "CVE-2020-26290" ],
  "summary" : "Critical security issues in XML encoding in github.com/dexidp/dex",
  "details" : "### Impact\n\nThe following vulnerabilities have been disclosed, which impact users leveraging the SAML connector:\n\nSignature Validation Bypass (CVE-2020-15216): https://github.com/russellhaering/goxmldsig/security/advisories/GHSA-q547-gmf8-8jr7\n\n`encoding/xml` instabilities:\n - [Element namespace prefix instability (CVE-2020-29511)](https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-elements.md)\n - [Attribute namespace prefix instability (CVE-2020-29509)](https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-attributes.md)\n - [Directive comment instability (CVE-2020-29510)](https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-directives.md)\n\n### Patches\n\nImmediately update to [Dex v2.27.0](https://github.com/dexidp/dex/releases/tag/v2.27.0).\n\n### Workarounds\n\nThere are no known workarounds.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/dexidp/dex"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.27.0"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/russellhaering/goxmldsig"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.1.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/dexidp/dex/security/advisories/GHSA-m9hp-7r99-94h5"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/russellhaering/goxmldsig/security/advisories/GHSA-q547-gmf8-8jr7"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-26290"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/dexidp/dex/commit/324b1c886b407594196113a3dbddebe38eecd4e8"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/russellhaering/goxmldsig/commit/f6188febf0c29d7ffe26a0436212b19cb9615e64"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/dexidp/dex/releases/tag/v2.27.0"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-attributes.md"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-directives.md"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-elements.md"
  }, {
    "type" : "WEB",
    "url" : "https://mattermost.com/blog/coordinated-disclosure-go-xml-vulnerabilities"
  }, {
    "type" : "WEB",
    "url" : "https://pkg.go.dev/vuln/GO-2020-0050"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-347" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-05-21T20:49:36Z",
    "nvd_published_at" : null
  }
}