# CVE-2021-21376: Information Exposure in OMERO.web

> OMERO.web exposes sensitive user information such as ID, name, and group membership on main webclient pages, allowing attackers to gather user data.

- **Severity:** Medium 6.4 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 23 Mar 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-gfp2-w5jm-955q, PYSEC-2021-31

## What is CVE-2021-21376?

CVE-2021-21376 is a medium-severity vulnerability in omero-web, published on 23 Mar 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

OMERO.web is open source Django-based software for managing microscopy imaging. OMERO.web before version 5.9.0 loads various information about the current user such as their id, name and the groups they are in, and these are available on the main webclient pages. This represents an information exposure vulnerability. Some additional information being loaded is not used by the webclient and is being removed in this release. This is fixed in version 5.9.0.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2021-21376?

3 open source packages ship an affected version, including omero-web. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `omero-web` | PyPI | All versions | 5.9.0 |
| `omero-web` | PyPI | All versions | 5.9.0 |
| `omero-web` | PyPI | All versions | 5.9.0 |

Products: Openmicroscopy Omero.web.

## How do I fix CVE-2021-21376?

Upgrade omero-web to 5.9.0 or later.

## Is CVE-2021-21376 being exploited?

There is no known exploitation of CVE-2021-21376 in the wild and no public exploit code.

## Other vulnerabilities in omero-web

- [CVE-2020-7932](https://insights.sbomify.com/CVE-2020-7932/): OMERO-web Sensitive Data Exposure (medium 5.7)
- [CVE-2021-21377](https://insights.sbomify.com/CVE-2021-21377/): Open Redirect in OMERO.web (medium 4.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21376 and fix it if it is affected.

What it is: CVE-2021-21376 is a medium-severity vulnerability in omero-web, published on 23 Mar 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-21376 in the wild and no public exploit code.

Affected packages and fixed versions:
- omero-web (PyPI): affected all versions; fixed in 5.9.0
- omero-web (PyPI): affected all versions; fixed in 5.9.0
- omero-web (PyPI): affected all versions; fixed in 5.9.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-21376/ (Markdown: https://insights.sbomify.com/CVE-2021-21376/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21376
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21376
- OSV: https://osv.dev/vulnerability/CVE-2021-21376

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21376/
Summaries are generated and may contain mistakes; the official description above is the record.