# CVE-2020-11995: Apache Dubbo default deserialization protocol Hessian2 cause CRE

> Attackers can execute arbitrary code via malicious Hessian2 deserialization in Apache Dubbo, requiring an upgrade to patched versions.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Jan 2021
- **Updated:** 13 Feb 2025
- **Also known as:** GHSA-74mg-6xqx-2vrq

## What is CVE-2020-11995?

CVE-2020-11995 is a critical unsafe deserialization vulnerability in Apache Dubbo, published on 11 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A deserialization vulnerability existed in dubbo 2.7.5 and its earlier versions, which could lead to malicious code execution. Most Dubbo users use Hessian2 as the default serialization/deserialization protool, during Hessian2 deserializing the HashMap object, some functions in the classes stored in HasMap will be executed after a series of program calls, however, those special functions may cause remote command execution. For example, the hashCode() function of the EqualsBean class in rome-1.7.0.jar will cause the remotely load malicious classes and execute malicious code by constructing a malicious request. This issue was fixed in Apache Dubbo 2.6.9 and 2.7.8.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2020-11995?

4 open source packages ship an affected version, including org.apache.dubbo:dubbo-parent. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.apache.dubbo:dubbo-parent` | Maven | All versions | 2.6.9 |
| `org.apache.dubbo:dubbo-parent` | Maven | All versions | 2.6.9 |
| `org.apache.dubbo:dubbo-parent` | Maven | From 2.7.0 | 2.7.8 |
| `org.apache.dubbo:dubbo-parent` | Maven | From 2.7.0 | 2.7.8 |

Products: Apache Dubbo.

## How do I fix CVE-2020-11995?

Upgrade org.apache.dubbo:dubbo-parent to a fixed version for your release line: 2.6.9 or 2.7.8.

## Is CVE-2020-11995 being exploited?

There is no known exploitation of CVE-2020-11995 in the wild and no public exploit code.

## Other vulnerabilities in Apache Dubbo

- [CVE-2023-29234](https://insights.sbomify.com/CVE-2023-29234/): Bypass serialize checks in Apache Dubbo (critical 9.8)
- [CVE-2023-46279](https://insights.sbomify.com/CVE-2023-46279/): Apache Dubbo: Bypass deny serialize list check in Apache Dubbo (critical 9.8)
- [CVE-2021-32824](https://insights.sbomify.com/CVE-2021-32824/): Regular expression Denial of Service in MooTools (critical 9.8)
- [CVE-2022-39198](https://insights.sbomify.com/CVE-2022-39198/): Apache Dubbo Hession Deserialization Vulnerability Gadgets Bypass (critical 9.8)
- [CVE-2021-43297](https://insights.sbomify.com/CVE-2021-43297/): Dubbo Hessian cause RCE when parse error (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-11995 and fix it if it is affected.

What it is: CVE-2020-11995 is a critical unsafe deserialization vulnerability in Apache Dubbo, published on 11 Jan 2021. 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-2020-11995 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.apache.dubbo:dubbo-parent (Maven): affected all versions; fixed in 2.6.9
- org.apache.dubbo:dubbo-parent (Maven): affected all versions; fixed in 2.6.9
- org.apache.dubbo:dubbo-parent (Maven): affected from 2.7.0; fixed in 2.7.8
- org.apache.dubbo:dubbo-parent (Maven): affected from 2.7.0; fixed in 2.7.8

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-2020-11995/ (Markdown: https://insights.sbomify.com/CVE-2020-11995/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-11995
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-11995
- OSV: https://osv.dev/vulnerability/CVE-2020-11995

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-11995/
Summaries are generated and may contain mistakes; the official description above is the record.