Security advisory

{
  "id": "b0d7635fe9b149787850730a502eec93560bf3e1fe8a9688975963c3d3c01652",
  "url": "https://osv.dev/vulnerability/CVE-2021-32635",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-32635",
    "summary": "Singularity is an open source container platform. In verions 3.7.2 and 3.7.3, Dde to incorrect use of a default URL, `singularity` action commands (`run`/`shell`/`exec`) specifying a container using a `library://` URI will always attempt to retrieve the container from the default remote endpoint (`cloud.sylabs.io`) rather than the configured remote endpoint. An attacker may be able to push a malicious container to the default remote endpoint with a URI that is identical to the URI used by a victim with a non-default remote endpoint, thus executing the malicious container. Only action commands (`run`/`shell`/`exec`) against `library://` URIs are affected. Other commands such as `pull` / `push` respect the configured remote endpoint. The vulnerability is patched in Singularity version 3.7.4. Two possible workarounds exist: Users can only interact with the default remote endpoint, or an installation can have an execution control list configured to restrict execution to containers signed with specific secure keys.",
    "evidence": "osv:CVE-2021-32635",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-32635",
      "aliases": [
        "CVE-2021-32635",
        "GHSA-5mv9-q7fq-9394"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/apptainer/singularity",
              "type": "GIT",
              "events": [
                {
                  "introduced": "47d3b5d415166bb3e0abba36c70714b53f240f70"
                },
                {
                  "last_affected": "6e59f31cb97ff59e323850aa1339a38a11358429"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:sylabs:singularity:3.7.2:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.7.2"
                      },
                      {
                        "last_affected": "3.7.2"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "cpe": "cpe:2.3:a:sylabs:singularity:3.7.3:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.7.3"
                      },
                      {
                        "last_affected": "3.7.3"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "3.7.2",
            "3.7.3",
            "v3.7.3",
            "v3.7.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-32635.json"
          }
        },
        {
          "ranges": [
            {
              "repo": "https://github.com/sylabs/singularity",
              "type": "GIT",
              "events": [
                {
                  "introduced": "47d3b5d415166bb3e0abba36c70714b53f240f70"
                },
                {
                  "last_affected": "6e59f31cb97ff59e323850aa1339a38a11358429"
                },
                {
                  "fixed": "a29667c1564e5a689719ca762feedf050ed4933f"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:sylabs:singularity:3.7.2:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.7.2"
                      },
                      {
                        "last_affected": "3.7.2"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "cpe": "cpe:2.3:a:sylabs:singularity:3.7.3:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.7.3"
                      },
                      {
                        "last_affected": "3.7.3"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "range": [
                      {
                        "fixed": "a29667c1564e5a689719ca762feedf050ed4933f"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v3.7.4"
                  }
                ]
              }
            }
          ],
          "versions": [
            "3.7.2",
            "3.7.3",
            "v3.7.3",
            "v3.7.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-32635.json"
          }
        }
      ],
      "modified": "2026-10-24T10:50:24.280791814Z",
      "provider": "osv",
      "references": [
        "https://github.com/sylabs/singularity/releases/tag/v3.7.4",
        "https://github.com/sylabs/singularity/security/advisories/GHSA-5mv9-q7fq-9394",
        "https://security.gentoo.org/glsa/202107-50"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-32635",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 442113,
  "published_at": "2021-05-28T21:15:09.02+00:00"
}