{"cve":"CVE-2021-32635","nvd":{"published":"2021-05-28T21:15:09.020","modified":"2026-06-17T03:53:19.233","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L","score":6.3},"cwes":["CWE-20","CWE-923"],"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","https://github.com/sylabs/singularity/releases/tag/v3.7.4","https://github.com/sylabs/singularity/security/advisories/GHSA-5mv9-q7fq-9394"],"products":["sylabs:singularity"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-32635","score":0.01415,"percentile":0.72751,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-5mv9-q7fq-9394","url":"https://osv.dev/vulnerability/GHSA-5mv9-q7fq-9394","summary":"Action Commands (run/shell/exec) Against Library URIs Ignore Configured Remote Endpoint","modified":"2026-07-08T06:28:19.961414839Z","packages":[{"ecosystem":"Go","name":"github.com/sylabs/singularity","purl":"pkg:golang/github.com/sylabs/singularity","ranges":[">=3.7.2 <3.7.4"],"fixed":["3.7.4"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}