Authentication Bypass in dex

緊急 9.6CVE-2020-26290 · CVE-2020-27847 · GHSA-2x32-jm95-2cpx · 28/12/2020 公開 · 17/06/2026 更新

要点

CVE-2020-26290 は github.com/dexidp/dex, github.com/russellhaering/goxmldsig, dex (linuxfoundation) に影響する深刻度「緊急」 (CVSS 9.6) の脆弱性です。
今後30日間に悪用される確率（EPSS）：0.99%（全脆弱性の 62.5% より高い）。
対処：2.27.0, 1.1.0 以降に更新してください。

パッケージ	影響を受けるバージョン	修正済みバージョン
github.com/dexidp/dex Go	`< 2.27.0`	`2.27.0`
github.com/russellhaering/goxmldsig Go	`< 1.1.0`	`1.1.0`
dex linuxfoundation	`< 2.27.0`	`2.27.0`

概要

A vulnerability exists in the SAML connector of the github.com/dexidp/dex library used to process SAML Signature Validation. This flaw allows an attacker to bypass SAML authentication. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability. This flaw affects dex versions before 2.27.0.

NVD の説明

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).