# CVE-2021-39152: A Server-Side Forgery Request vulnerability in XStream via HashMap unmarshaling

> Remote attackers can access internal resources via SSRF in XStream when using default security settings on Java 8-14.

- **Severity:** High 8.5 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Aug 2021
- **Updated:** 7 Oct 2026
- **Also known as:** DEBIAN-CVE-2021-39152, GHSA-xw4p-crpj-vjx2, UBUNTU-CVE-2021-39152

## What is CVE-2021-39152?

CVE-2021-39152 is a high-severity server-side request forgery vulnerability in Debian Debian Linux, published on 23 Aug 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker to request data from internal resources that are not publicly available only by manipulating the processed input stream with a Java runtime version 14 to 8. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. If you rely on XStream's default blacklist of the [Security Framework](https://x-stream.github.io/security.html#framework), you will have to use at least version 1.4.18.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2021-39152?

2 open source packages ship an affected version, including com.thoughtworks.xstream:xstream. It affects 15 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `com.thoughtworks.xstream:xstream` | Maven | All versions | 1.4.18 |
| `com.thoughtworks.xstream:xstream` | Maven | All versions | 1.4.18 |

Products: Debian Debian Linux, Fedoraproject Fedora, Netapp Snapmanager, Oracle Business Activity Monitoring, Oracle Commerce Guided Search, Oracle Communications Billing and Revenue Management Elastic Charging Engine, Oracle Communications Cloud Native Core Automated Test Suite, Oracle Communications Cloud Native Core Binding Support Function, Oracle Communications Cloud Native Core Policy, Oracle Communications Unified Inventory Management, Oracle Retail Xstore Point of Service, Oracle Utilities Framework, Oracle Utilities Testing Accelerator, Oracle Webcenter Portal, Xstream Xstream.

## How do I fix CVE-2021-39152?

Upgrade com.thoughtworks.xstream:xstream to 1.4.18 or later.

## Is CVE-2021-39152 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-39152 exists.

Public exploit code:

- XStream <1.4.18 - Server-Side Request Forgery (nuclei): http/cves/2021/CVE-2021-39152.yaml

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-39152 and fix it if it is affected.

What it is: CVE-2021-39152 is a high-severity server-side request forgery vulnerability in Debian Debian Linux, published on 23 Aug 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-39152 exists.

Affected packages and fixed versions:
- com.thoughtworks.xstream:xstream (Maven): affected all versions; fixed in 1.4.18
- com.thoughtworks.xstream:xstream (Maven): affected all versions; fixed in 1.4.18

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-2021-39152/ (Markdown: https://insights.sbomify.com/CVE-2021-39152/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-39152
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-39152
- OSV: https://osv.dev/vulnerability/CVE-2021-39152

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-39152/
Summaries are generated and may contain mistakes; the official description above is the record.