# CVE-2021-27099: Missing authorization in n/a

> Attackers can obtain arbitrary SPIFFE IDs by manipulating EC2 tags if agent ID templating is enabled, bypassing identity controls.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/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:** Not needed
- **Fix available:** No
- **Published:** 5 Mar 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-q7gm-mjrg-44h9

## What is CVE-2021-27099?

CVE-2021-27099 is a medium-severity missing authorization vulnerability in n/a, published on 5 Mar 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

In SPIRE before versions 0.8.5, 0.9.4, 0.10.2, 0.11.3 and 0.12.1, the "aws_iid" Node Attestor improperly normalizes the path provided through the agent ID templating feature, which may allow the issuance of an arbitrary SPIFFE ID within the same trust domain, if the attacker controls the value of an EC2 tag prior to attestation, and the attestor is configured for agent ID templating where the tag value is the last element in the path. This issue has been fixed in SPIRE versions 0.11.3 and 0.12.1

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2021-27099?

It affects 1 product.


Products: Cncf Spire.

## How do I fix CVE-2021-27099?

No fix has been published for CVE-2021-27099 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-27099 being exploited?

There is no known exploitation of CVE-2021-27099 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-27098](https://insights.sbomify.com/CVE-2021-27098/): Legacy Node API Allows Impersonation in github.com/spiffe/spire/pkg/server/endpoints/node (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27099 and fix it if it is affected.

What it is: CVE-2021-27099 is a medium-severity missing authorization vulnerability in n/a, published on 5 Mar 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-27099 in the wild and no public exploit code.

Affected product: n/a. 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-2021-27099/ (Markdown: https://insights.sbomify.com/CVE-2021-27099/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27099
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27099
- OSV: https://osv.dev/vulnerability/CVE-2021-27099

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27099/
Summaries are generated and may contain mistakes; the official description above is the record.