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GHSA-m9hp-7r99-94h5

CRITICAL

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

Also known asCVE-2020-26290
Published
Dec 20, 2021
Updated
Mar 13, 2026
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
1.0%probability of exploitation in next 30 days
Lower Risk58th percentile+0.48%
0.00%0.49%0.98%1.48%0.5%1.0%Dec 25Apr 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

2 pkgs affected
🐹github.com/dexidp/dex🐹github.com/russellhaering/goxmldsig

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

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:

Patches

Immediately update to Dex v2.27.0.

Workarounds

There are no known workarounds.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/dexidp/dexall versions2.27.0
🐹Gogithub.com/russellhaering/goxmldsigall versions1.1.0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/dexidp/dex. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update github.com/dexidp/dex to 2.27.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-m9hp-7r99-94h5 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-m9hp-7r99-94h5 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-m9hp-7r99-94h5. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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) - [D
O3 Security · Impact-Aware SCA

Is GHSA-m9hp-7r99-94h5 in your dependencies?

O3 detects GHSA-m9hp-7r99-94h5 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.