Security advisory

{
  "id": "d612feaeca1310d4e886e4f8444c0068f9a263368fa3e7a85236c25abe0a3517",
  "url": "https://osv.dev/vulnerability/CVE-2021-3856",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-3856",
    "summary": "ClassLoaderTheme and ClasspathThemeResourceProviderFactory allows reading any file available as a resource to the classloader. By sending requests for theme resources with a relative path from an external HTTP client, the client will receive the content of random files if available.",
    "evidence": "osv:CVE-2021-3856",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-3856",
      "aliases": [
        "CVE-2021-3856",
        "GHSA-3w4v-rvc4-2xpw"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/keycloak/keycloak",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "843566019e09d15fa0e4778356463bc9a430e965"
                },
                {
                  "fixed": "73f0474008e1bebd0733e62a22aceda9e5de6743"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:redhat:keycloak:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "15.1.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "73f0474008e1bebd0733e62a22aceda9e5de6743"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.4.0.Test",
            "1.3.0.Final",
            "1.1.0.Beta2",
            "1.0.0.Final",
            "1.0-final",
            "1.0-rc-1",
            "1.0-beta-4",
            "1.0-beta-2",
            "1.0-beta-1",
            "1.0-alpha-3",
            "1.0-alpha-2",
            "1.0-alpha-1",
            "1.0-alpha-1-12062013"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3856.json",
            "vanir_signatures": [
              {
                "id": "CVE-2021-3856-1dad238c",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "124260399539281011717707373586744147021",
                    "273546477869425480957980733809903113856",
                    "285018114609585019930830636075742367167",
                    "133178131592467951898160846919801786489",
                    "96407110543803275689348891033921234091"
                  ]
                },
                "source": "https://github.com/keycloak/keycloak/commit/73f0474008e1bebd0733e62a22aceda9e5de6743",
                "target": {
                  "file": "services/src/main/java/org/keycloak/theme/ClassLoaderTheme.java"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2021-3856-2ade5fb0",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "121861020690458924525486788093213951948",
                    "248515847350033744246149201106405994849",
                    "3330082002857581691640005490138153212",
                    "225176885544135933599938528445378366721"
                  ]
                },
                "source": "https://github.com/keycloak/keycloak/commit/73f0474008e1bebd0733e62a22aceda9e5de6743",
                "target": {
                  "file": "services/src/main/java/org/keycloak/theme/ClasspathThemeResourceProviderFactory.java"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2021-3856-3c06b61d",
                "digest": {
                  "length": 123,
                  "function_hash": "173054477908208581461759922352527267037"
                },
                "source": "https://github.com/keycloak/keycloak/commit/73f0474008e1bebd0733e62a22aceda9e5de6743",
                "target": {
                  "file": "services/src/main/java/org/keycloak/theme/ClasspathThemeResourceProviderFactory.java",
                  "function": "getResourceAsStream"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2021-3856-67fb8d24",
                "digest": {
                  "length": 91,
                  "function_hash": "163715556613522604159357137207365211778"
                },
                "source": "https://github.com/keycloak/keycloak/commit/73f0474008e1bebd0733e62a22aceda9e5de6743",
                "target": {
                  "file": "services/src/main/java/org/keycloak/theme/ClassLoaderTheme.java",
                  "function": "getResourceAsStream"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T14:26:37Z"
          }
        }
      ],
      "modified": "2026-10-20T14:26:37.166486374Z",
      "provider": "osv",
      "references": [
        "https://access.redhat.com/security/cve/CVE-2021-3856",
        "https://bugzilla.redhat.com/show_bug.cgi?id=2010164",
        "https://issues.redhat.com/browse/KEYCLOAK-19422",
        "https://github.com/keycloak/keycloak/commit/73f0474008e1bebd0733e62a22aceda9e5de6743",
        "https://github.com/keycloak/keycloak/pull/8588"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-3856",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 388993,
  "published_at": "2022-08-26T16:15:09.57+00:00"
}