{"id":"CVE-2021-32635","aliases":["GHSA-5mv9-q7fq-9394"],"url":"https://o3.security/vulnerability/CVE-2021-32635","summary":"Action Commands (run/shell/exec) Against Library URIs Ignore Configured Remote Endpoint","details":"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.","published":"2021-05-28T21:15:09.020Z","modified":"2026-08-27T08:14:40.583156Z","cvss":{"score":6.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/sylabs/singularity","fixedVersion":"3.7.4"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/sylabs/singularity/releases/tag/v3.7.4"},{"type":"ADVISORY","url":"https://github.com/sylabs/singularity/security/advisories/GHSA-5mv9-q7fq-9394"},{"type":"ADVISORY","url":"https://security.gentoo.org/glsa/202107-50"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-27T08:14:40.583156Z"}}