# CVE-2021-21324: Insecure Direct Object Reference (IDOR) on "Solutions"

> An authenticated attacker can enumerate user logins and other data by manipulating parameters in the GLPI knowbase search form.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/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:** No
- **Published:** 8 Mar 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-jvwm-gq36-3v7v, UBUNTU-CVE-2021-21324

## What is CVE-2021-21324?

CVE-2021-21324 is a medium-severity vulnerability in Glpi-Project Glpi, published on 8 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

GLPI is an open-source asset and IT management software package that provides ITIL Service Desk features, licenses tracking and software auditing. In GLPI before version 9.5.4 there is an Insecure Direct Object Reference (IDOR) on "Solutions". This vulnerability gives an unauthorized user the ability to enumerate GLPI items names (including users logins) using the knowbase search form (requires authentication). To Reproduce: Perform a valid authentication at your GLPI instance, Browse the ticket list and select any open ticket, click on Solution form, then Search a solution form that will redirect you to the endpoint /"glpi/front/knowbaseitem.php?item_itemtype=Ticket&item_items_id=18&forcetab=Knowbase$1", and the item_itemtype=Ticket parameter present in the previous URL will point to the PHP alias of glpi_tickets table, so just replace it with "Users" to point to glpi_users table instead; in the same way, item_items_id=18 will point to the related column id, so changing it too you should be able to enumerate all the content which has an alias. Since such id(s) are obviously incremental, a malicious party could exploit the vulnerability simply by guessing-based attempts.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2021-21324?

It affects 1 product.


Products: Glpi-Project Glpi.

## How do I fix CVE-2021-21324?

No fix has been published for CVE-2021-21324 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-21324 being exploited?

There is no known exploitation of CVE-2021-21324 in the wild and no public exploit code.

## Other vulnerabilities in Glpi-Project Glpi

- [CVE-2022-35914](https://insights.sbomify.com/CVE-2022-35914/): Teclib GLPI Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2023-42802](https://insights.sbomify.com/CVE-2023-42802/): GLPI vulnerable to unallowed PHP script execution (critical 10.0)
- [CVE-2023-28849](https://insights.sbomify.com/CVE-2023-28849/): GLPI vulnerable to SQL injection and Stored XSS via inventory agent request (critical 10.0)
- [CVE-2022-35947](https://insights.sbomify.com/CVE-2022-35947/): SQL injection in GLPI (critical 10.0)
- [CVE-2022-31056](https://insights.sbomify.com/CVE-2022-31056/): SQL injection with _actor parameter in GLPI (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21324 and fix it if it is affected.

What it is: CVE-2021-21324 is a medium-severity vulnerability in Glpi-Project Glpi, published on 8 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-2021-21324 in the wild and no public exploit code.

Affected product: Glpi-Project Glpi. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2021-21324/ (Markdown: https://insights.sbomify.com/CVE-2021-21324/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21324
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21324
- OSV: https://osv.dev/vulnerability/CVE-2021-21324

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21324/
Summaries are generated and may contain mistakes; the official description above is the record.