What’s Vulnerable › Vulnerabilities

CVE-2021-21377: Open Redirect in OMERO.web

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-03-23 · updated 2026-06-17
• Weakness: CWE-601

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.

Affected products

• omero-web: before 5.9.0 — fixed in 5.9.0

How to fix

Upgrade to a fixed version: omero-web 5.9.0. Check the vendor advisory for mitigations.

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/
• 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/

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