# CVE-2020-19676: Incorrect Access Control in Nacos

> Unauthenticated attackers can access service details and list interfaces in Nacos, leading to unauthorized information disclosure.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Sep 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-qf76-pr7x-h7r4

## What is CVE-2020-19676?

CVE-2020-19676 is a medium-severity missing authorization vulnerability in n/a, published on 30 Sep 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Nacos 1.1.4 is affected by: Incorrect Access Control. An environment can be set up locally to get the service details interface. Then other Nacos service names can be accessed through the service list interface. Service details can then be accessed when not logged in. (detail:https://github.com/alibaba/nacos/issues/2284)

## Which versions are affected by CVE-2020-19676?

2 open source packages ship an affected version, including com.alibaba.nacos:nacos-common. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `com.alibaba.nacos:nacos-common` | Maven | All versions | 1.2.0 |
| `com.alibaba.nacos:nacos-common` | Maven | All versions | 1.2.0 |

Products: Alibaba Nacos.

## How do I fix CVE-2020-19676?

Upgrade com.alibaba.nacos:nacos-common to 1.2.0 or later.

## Is CVE-2020-19676 being exploited?

There is no known exploitation of CVE-2020-19676 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-43116](https://insights.sbomify.com/CVE-2021-43116/): Use of Hard-coded Credentials in Nacos (high 8.8)
- [CVE-2021-29441](https://insights.sbomify.com/CVE-2021-29441/): Authentication bypass (high 8.6)
- [CVE-2021-29442](https://insights.sbomify.com/CVE-2021-29442/): Authentication bypass (high 8.6)
- [CVE-2021-44667](https://insights.sbomify.com/CVE-2021-44667/): Cross-site Scripting in Nacos (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-19676 and fix it if it is affected.

What it is: CVE-2020-19676 is a medium-severity missing authorization vulnerability in n/a, published on 30 Sep 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-19676 in the wild and no public exploit code.

Affected packages and fixed versions:
- com.alibaba.nacos:nacos-common (Maven): affected all versions; fixed in 1.2.0
- com.alibaba.nacos:nacos-common (Maven): affected all versions; fixed in 1.2.0

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-2020-19676/ (Markdown: https://insights.sbomify.com/CVE-2020-19676/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-19676
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-19676
- OSV: https://osv.dev/vulnerability/CVE-2020-19676

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-19676/
Summaries are generated and may contain mistakes; the official description above is the record.