{"cve":"CVE-2021-21377","nvd":{"published":"2021-03-23T16:15:14.283","modified":"2026-06-17T03:35:26.587","status":"Modified","description":"OMERO.web is open source Django-based software for managing microscopy imaging. OMERO.web before version 5.9.0 supports redirection to a given URL after performing login or switching the group context. These URLs are not validated, allowing redirection to untrusted sites. OMERO.web 5.9.0 adds URL validation before redirecting. External URLs are not considered valid, unless specified in the omero.web.redirect_allowed_hosts setting.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","score":5.4},"cwes":["CWE-601"],"references":["https://github.com/ome/omero-web/blob/master/CHANGELOG.md#590-march-2021","https://github.com/ome/omero-web/commit/952f8e5d28532fbb14fb665982211329d137908c","https://github.com/ome/omero-web/security/advisories/GHSA-g4rf-pc26-6hmr","https://pypi.org/project/omero-web/","https://www.openmicroscopy.org/security/advisories/2021-SV2/"],"products":["openmicroscopy:omero.web"],"source":"nvd","synced_at":"2026-10-19T21:15:50.279857260+00:00"},"epss":{"cve":"CVE-2021-21377","score":0.00826,"percentile":0.57463,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-g4rf-pc26-6hmr","url":"https://osv.dev/vulnerability/GHSA-g4rf-pc26-6hmr","summary":"OMERO webclient does not validate URL redirects on login or switching group.","modified":"2026-07-08T06:27:39.407297766Z","packages":[{"ecosystem":"PyPI","name":"omero-web","purl":"pkg:pypi/omero-web","ranges":["<5.9.0"],"fixed":["5.9.0"]}]},{"id":"PYSEC-2021-32","url":"https://osv.dev/vulnerability/PYSEC-2021-32","summary":"","modified":"2023-11-08T04:04:43.727578Z","packages":[{"ecosystem":"PyPI","name":"omero-web","purl":"pkg:pypi/omero-web","ranges":["<5.9.0"],"fixed":["5.9.0"]}]}],"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."]}