Critical security issues in XML encoding in github.com/dexidp/dex

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2020-26290: 0.99% estimated exploitation activity in the next 30 days; percentile 62.55 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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) - Attribute namespace prefix instability (CVE-2020-29509) - Directive comment instability (CVE-2020-29510) Patches Immediately update to Dex v2.27.0. Workarounds There are no known workarounds.

Published by the source

20 Dec 2021, 17:53 UTC

Last modified by the source

2 Oct 2023, 13:39 UTC

Source last checked

26 Oct 2026, 14:59 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-m9hp-7r99-94h5

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2020-26290

Advisory: Critical security issues in XML encoding in github.com/dexidp/dex
IDs: CVE-2020-26290, GHSA-m9hp-7r99-94h5
Record: https://patchnext.com/advisories/cve-2020-26290 (revision 1, source checked 26 Oct 2026, 14:59 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/russellhaering/goxmldsig 1.1.0; github.com/dexidp/dex 2.27.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/russellhaering/goxmldsig: affected < 1.1.0; fixed in 1.1.0
- Go github.com/dexidp/dex: affected < 2.27.0; fixed in 2.27.0

## Suggested inspection (read-only)
- Go github.com/russellhaering/goxmldsig: check the installed version with your package manager.
- Go github.com/dexidp/dex: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/russellhaering/goxmldsig, github.com/dexidp/dex.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-m9hp-7r99-94h5 (GitHub-reviewed advisory GHSA-m9hp-7r99-94h5 lists affected ranges: Go github.com/dexidp/dex >=0 =0 <1.1.0)

Commands are suggestions: review each one before running it.