# CVE-2021-20077: Information disclosure in Tenable Nessus Agent

> A privileged attacker can obtain the IAM role security token from the local host when the Nessus Agent is linked on an EC2 instance.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Mar 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-fh62-2wf5-r836

## What is CVE-2021-20077?

CVE-2021-20077 is a medium-severity vulnerability in Tenable Nessus Agent, published on 19 Mar 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Nessus Agent versions 7.2.0 through 8.2.2 were found to inadvertently capture the IAM role security token on the local host during initial linking of the Nessus Agent when installed on an Amazon EC2 instance. This could allow a privileged attacker to obtain the token.

## Which versions are affected by CVE-2021-20077?

It affects 1 product.


Products: Tenable Nessus Agent.

## How do I fix CVE-2021-20077?

No fix has been published for CVE-2021-20077 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20077 being exploited?

There is no known exploitation of CVE-2021-20077 in the wild and no public exploit code.

## Other vulnerabilities in Tenable Nessus Agent

- [CVE-2026-15265](https://insights.sbomify.com/CVE-2026-15265/): Tenable Agent Path Traversal Leading to Remote Code Execution (critical 9.3)
- [CVE-2025-36633](https://insights.sbomify.com/CVE-2025-36633/): Local Privilege Escalation (high 8.8)
- [CVE-2025-36631](https://insights.sbomify.com/CVE-2025-36631/): Local Privilege Escalation (high 8.4)
- [CVE-2025-36632](https://insights.sbomify.com/CVE-2025-36632/): Local Privilege Escalation (high 7.8)
- [CVE-2021-20117](https://insights.sbomify.com/CVE-2021-20117/): Privilege escalation in Nessus Agent (medium 6.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20077 and fix it if it is affected.

What it is: CVE-2021-20077 is a medium-severity vulnerability in Tenable Nessus Agent, published on 19 Mar 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-20077 in the wild and no public exploit code.

Affected product: Tenable Nessus Agent. 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-2021-20077/ (Markdown: https://insights.sbomify.com/CVE-2021-20077/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20077
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20077
- OSV: https://osv.dev/vulnerability/CVE-2021-20077

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20077/
Summaries are generated and may contain mistakes; the official description above is the record.