GHSA-652X-M2GR-HPPM

Vulnerability from github – Published: 2025-07-30 16:21 – Updated: 2025-07-30 16:21
VLAI?
Summary
OAuth2-Proxy's `--gitlab-group` GitLab Group Authorization config flag stopped working in v7.0.0
Details

The --gitlab-group flag for group-based authorization in the GitLab provider stopped working in the v7.0.0 release.

Regardless of the flag settings, authorization wasn't restricted. Additionally, any authenticated users had whichever groups were set in --gitlab-group added to the new X-Forwarded-Groups header to the upstream application.

While adding GitLab project based authorization support in #630, a bug was introduced where the user session's groups field was populated with the --gitlab-group config entries instead of pulling the individual user's group membership from the GitLab Userinfo endpoint. When the session groups where compared against the allowed groups for authorization, they matched improperly (since both lists were populated with the same data) so authorization was allowed.

Impact

This impacts GitLab Provider users who relies on group membership for authorization restrictions. Any authenticated users in your GitLab environment can access your applications regardless of --gitlab-group membership restrictions.

Patches

This is patched in v7.1.0

Workarounds

There is no workaround for the Group membership bug. But --gitlab-project can be set to use Project membership as the authorization checks instead of groups; it is not broken.

Severity ?
5.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/oauth2-proxy/oauth2-proxy/v7"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-21411"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-285",
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-07-30T16:21:04Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "The `--gitlab-group` flag for group-based authorization in the GitLab provider stopped working in the v7.0.0 release.\n\nRegardless of the flag settings, authorization wasn\u0027t restricted. Additionally, any authenticated users had whichever groups were set in `--gitlab-group` added to the new `X-Forwarded-Groups` header to the upstream application.\n\nWhile adding GitLab project based authorization support in #630, a bug was introduced where the user session\u0027s groups field was populated with the `--gitlab-group` config entries instead of pulling the individual user\u0027s group membership from the GitLab Userinfo endpoint. When the session groups where compared against the allowed groups for authorization, they matched improperly (since both lists were populated with the same data) so authorization was allowed.\n\n### Impact\nThis impacts GitLab Provider users who relies on group membership for authorization restrictions. Any authenticated users in your GitLab environment can access your applications regardless of `--gitlab-group` membership restrictions.\n\n### Patches\nThis is patched in v7.1.0\n\n### Workarounds\nThere is no workaround for the Group membership bug. But `--gitlab-project` can be set to use Project membership as the authorization checks instead of groups; it is not broken.",
  "id": "GHSA-652x-m2gr-hppm",
  "modified": "2025-07-30T16:21:04Z",
  "published": "2025-07-30T16:21:04Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-652x-m2gr-hppm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-21411"
    },
    {
      "type": "WEB",
      "url": "https://github.com/oauth2-proxy/oauth2-proxy/commit/0279fa7dff1752f1710707dbd1ffac839de8bbfc"
    },
    {
      "type": "WEB",
      "url": "https://docs.gitlab.com/ee/user/group"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/oauth2-proxy/oauth2-proxy"
    },
    {
      "type": "WEB",
      "url": "https://github.com/oauth2-proxy/oauth2-proxy/releases/tag/v7.1.0"
    },
    {
      "type": "WEB",
      "url": "https://pkg.go.dev/github.com/oauth2-proxy/oauth2-proxy/v7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "OAuth2-Proxy\u0027s `--gitlab-group` GitLab Group Authorization config flag stopped working in v7.0.0"
}


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