# CVE-2021-21539: Race condition in Integrated Dell Remote Access Controller (iDRAC)

> Remote authenticated attackers can exploit a race condition in Dell iDRAC9 to gain elevated privileges during concurrent web interface access.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:H/A:L`)
- **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:** 30 Apr 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-mvg3-9cx3-qjv5

## What is CVE-2021-21539?

CVE-2021-21539 is a medium-severity vulnerability in Integrated Dell Remote Access Controller (iDRAC), published on 30 Apr 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

Dell EMC iDRAC9 versions prior to 4.40.00.00 contain a Time-of-check Time-of-use (TOCTOU) race condition vulnerability. A remote authenticated attacker could potentially exploit this vulnerability to gain elevated privileges when a user with higher privileges is simultaneously accessing iDRAC through the web interface.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2021-21539?

It affects 1 product.


Products: Dell Idrac9 Firmware.

## How do I fix CVE-2021-21539?

No fix has been published for CVE-2021-21539 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-21539 being exploited?

There is no known exploitation of CVE-2021-21539 in the wild and no public exploit code.

## Other vulnerabilities in Integrated Dell Remote Access Controller (iDRAC)

- [CVE-2021-21538](https://insights.sbomify.com/CVE-2021-21538/): Auth bypass in Integrated Dell Remote Access Controller (iDRAC) (critical 9.6)
- [CVE-2019-3706](https://insights.sbomify.com/CVE-2019-3706/): Web Interface Authentication Bypass Vulnerability (high 8.6)
- [CVE-2019-3707](https://insights.sbomify.com/CVE-2019-3707/): WS-MAN Authentication Bypass Vulnerability (high 8.6)
- [CVE-2020-5366](https://insights.sbomify.com/CVE-2020-5366/): Path traversal in Integrated Dell Remote Access Controller (iDRAC) (high 7.1)
- [CVE-2018-1249](https://insights.sbomify.com/CVE-2018-1249/): Security feature bypass in iDRAC9 (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21539 and fix it if it is affected.

What it is: CVE-2021-21539 is a medium-severity vulnerability in Integrated Dell Remote Access Controller (iDRAC), published on 30 Apr 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-2021-21539 in the wild and no public exploit code.

Affected product: Integrated Dell Remote Access Controller (iDRAC). 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-2021-21539/ (Markdown: https://insights.sbomify.com/CVE-2021-21539/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21539
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21539
- OSV: https://osv.dev/vulnerability/CVE-2021-21539

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-21539/
Summaries are generated and may contain mistakes; the official description above is the record.