CVE-2020-26290

Name: CVE-2020-26290
Creator: NVD / NIST
Published: 2020-12-28T20:15:12.493+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.6/10EPSS 0.98%

Last modified Jun 17, 2026

CVE-2020-26290 is a critical-severity vulnerability rated 9.6/10 on the CVSS scale. Dex is a federated OpenID Connect provider written in Go. In Dex before version 2.27.0 there is a critical set of vulnerabilities which impacts users leveraging the SAML connector. EPSS estimates a 0.98% chance of exploitation in the next 30 days.

Description

Dex is a federated OpenID Connect provider written in Go. In Dex before version 2.27.0 there is a critical set of vulnerabilities which impacts users leveraging the SAML connector. The vulnerabilities enables potential signature bypass due to issues with XML encoding in the underlying Go library. The vulnerabilities have been addressed in version 2.27.0 by using the xml-roundtrip-validator from Mattermost (see related references).

Metrics

CVSS 3.1

9.6/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

EPSS Probability

0.98%

57.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-347

Affected Software

Vendor	Product	Versions
Linuxfoundation	Dex	< 2.27.0

References

https://github.com/dexidp/dex/commit/324b1c886b407594196113a3dbddebe38eecd4e8Patch, Third Party Advisory
https://github.com/dexidp/dex/releases/tag/v2.27.0Third Party Advisory
https://github.com/dexidp/dex/security/advisories/GHSA-m9hp-7r99-94h5Third Party Advisory
https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-attributes.mdNot Applicable, Third Party Advisory
https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-directives.mdNot Applicable, Third Party Advisory
https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-elements.mdNot Applicable, Third Party Advisory
https://github.com/russellhaering/goxmldsig/security/advisories/GHSA-q547-gmf8-8jr7Not Applicable, Third Party Advisory
https://mattermost.com/blog/coordinated-disclosure-go-xml-vulnerabilities/Not Applicable, Third Party Advisory
https://github.com/dexidp/dex/commit/324b1c886b407594196113a3dbddebe38eecd4e8Patch, Third Party Advisory
https://github.com/dexidp/dex/releases/tag/v2.27.0Third Party Advisory
https://github.com/dexidp/dex/security/advisories/GHSA-m9hp-7r99-94h5Third Party Advisory
https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-attributes.mdNot Applicable, Third Party Advisory
https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-directives.mdNot Applicable, Third Party Advisory
https://github.com/mattermost/xml-roundtrip-validator/blob/master/advisories/unstable-elements.mdNot Applicable, Third Party Advisory
https://github.com/russellhaering/goxmldsig/security/advisories/GHSA-q547-gmf8-8jr7Not Applicable, Third Party Advisory
https://mattermost.com/blog/coordinated-disclosure-go-xml-vulnerabilities/Not Applicable, Third Party Advisory

Timeline

Published: Dec 28, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-26290?

How severe is CVE-2020-26290?

CVE-2020-26290 has a CVSS score of 9.6/10 (CRITICAL severity). The EPSS model estimates a 0.98% probability of exploitation in the next 30 days.

How do I fix CVE-2020-26290?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-26290?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST