Security advisory
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-21377
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 11:32 UTC · Revision 1
Source evidence
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.
osv:CVE-2021-21377
Complete source record
{
"id": "67467c571cba19624e858d5dc3760002a8b983665a8788b9f285433c26da5153",
"url": "https://osv.dev/vulnerability/CVE-2021-21377",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-21377",
"summary": "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.",
"evidence": "osv:CVE-2021-21377",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2021-21377",
"aliases": [
"CVE-2021-21377",
"GHSA-g4rf-pc26-6hmr",
"PYSEC-2021-32"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/ome/omero-web",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "1303ae337622820b5eacb3967f236ec113e32ef1"
},
{
"fixed": "952f8e5d28532fbb14fb665982211329d137908c"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:openmicroscopy:omero.web:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "5.9.0"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "952f8e5d28532fbb14fb665982211329d137908c"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"v5.8.1",
"v5.8.0",
"v5.7.1",
"v5.7.0",
"v5.6.3",
"v5.6.2",
"v5.6.1",
"v5.6.0",
"v5.6.dev7",
"v5.6.dev6",
"v5.6.dev5",
"v5.6.dev4",
"v5.6.dev3",
"v5.6.dev2",
"v5.6.dev1",
"v5.5.dev2",
"v5.5.dev1"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-21377.json"
}
}
],
"modified": "2026-10-20T10:54:29.623641762Z",
"provider": "osv",
"references": [
"https://github.com/ome/omero-web/blob/master/CHANGELOG.md#590-march-2021",
"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/",
"https://github.com/ome/omero-web/commit/952f8e5d28532fbb14fb665982211329d137908c"
],
"provider_metadata": {}
},
"related_cves": [
{
"value": "CVE-2021-21377",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 385454,
"published_at": "2021-03-23T16:15:14.283+00:00"
}