CVE-2026-41059: Github.com/oauth2 proxy/oauth2 proxy/v7 Authentication Bypass Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-pxq7-h93f-9jrg",
  "modified" : "2026-04-24T20:40:56Z",
  "published" : "2026-04-15T19:24:13Z",
  "aliases" : [ "CVE-2026-41059" ],
  "summary" : "OAuth2 Proxy has an Authentication Bypass via Fragment Confusion in skip_auth_routes and skip_auth_regex",
  "details" : "### Impact\n\nA configuration-dependent authentication bypass exists in OAuth2 Proxy.\n\nDeployments are affected when all of the following are true:\n\n* Use of `skip_auth_routes` or the legacy `skip_auth_regex` * Use of patterns that can be widened by attacker-controlled suffixes,    such as `^/foo/.*/bar$` causing potential exposure of `/foo/secret` * Protected upstream applications that interpret `#` as a fragment delimiter    or otherwise route the request to the protected base path\n\nIn deployments that rely on these settings, an unauthenticated attacker can send a crafted request containing a number sign in the path, including the browser-safe encoded form `%23`, so that OAuth2 Proxy matches a public allowlist rule while the backend serves a protected resource.\n\nDeployments that do not use these skip-auth options, or that only allow exact public paths with tightly scoped method and path rules, **ARE NOT** affected.\n\n### Patches\n\nA fix has been implemented to normalize request paths more conservatively before skip-auth matching so fragment content does not influence allowlist decisions.\n\nReleased as part of `v7.15.2`\n\n### Workarounds\n\nUsers who cannot upgrade immediately can reduce exposure by tightening or removing `skip_auth_routes` and `skip_auth_regex` rules, especially patterns that use broad wildcards across path segments.\n\nRecommended mitigations:\n\n* Replace broad rules with exact, anchored public paths and explicit HTTP methods\n* Reject requests whose path contains `%23` or `#` at the ingress, load balancer, or WAF level\n* Avoid placing sensitive application paths behind broad `skip_auth_routes` rules",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/oauth2-proxy/oauth2-proxy/v7"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.5.0"
      }, {
        "fixed" : "7.15.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-pxq7-h93f-9jrg"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-41059"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/oauth2-proxy/oauth2-proxy"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-288" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-15T19:24:13Z",
    "nvd_published_at" : "2026-04-22T00:16:27Z"
  }
}