CVE-2021-21377

Name: CVE-2021-21377
Creator: NVD / NIST
Published: 2021-03-23T16:15:14.283+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.4/10EPSS 0.83%

Last modified Jun 17, 2026

CVE-2021-21377 is a medium-severity vulnerability rated 5.4/10 on the CVSS scale. 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. EPSS estimates a 0.83% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

5.4/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

0.83%

52.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-601

Affected Software

Vendor	Product	Versions
Openmicroscopy	Omero.Web	< 5.9.0

References

https://github.com/ome/omero-web/blob/master/CHANGELOG.md#590-march-2021Release Notes, Third Party Advisory
https://github.com/ome/omero-web/commit/952f8e5d28532fbb14fb665982211329d137908cPatch, Third Party Advisory
https://github.com/ome/omero-web/security/advisories/GHSA-g4rf-pc26-6hmrThird Party Advisory
https://pypi.org/project/omero-web/Third Party Advisory
https://www.openmicroscopy.org/security/advisories/2021-SV2/Vendor Advisory
https://github.com/ome/omero-web/blob/master/CHANGELOG.md#590-march-2021Release Notes, Third Party Advisory
https://github.com/ome/omero-web/commit/952f8e5d28532fbb14fb665982211329d137908cPatch, Third Party Advisory
https://github.com/ome/omero-web/security/advisories/GHSA-g4rf-pc26-6hmrThird Party Advisory
https://pypi.org/project/omero-web/Third Party Advisory
https://www.openmicroscopy.org/security/advisories/2021-SV2/Vendor Advisory

Timeline

Published: Mar 23, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21377?

How severe is CVE-2021-21377?

CVE-2021-21377 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 0.83% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21377?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21377?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST