# CVE-2020-16171: Server-side request forgery in n/a

> Attackers can exploit a custom header in Acronis Cyber Backup API endpoints to perform Server-Side Request Forgery against internal localhost services.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Sep 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-2347-fp75-m9xc

## What is CVE-2020-16171?

CVE-2020-16171 is a medium-severity server-side request forgery vulnerability in n/a, published on 21 Sep 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Acronis Cyber Backup before 12.5 Build 16342. Some API endpoints on port 9877 under /api/ams/ accept an additional custom Shard header. The value of this header is afterwards used in a separate web request issued by the application itself. This can be abused to conduct SSRF attacks against otherwise unreachable Acronis services that are bound to localhost such as the NotificationService on 127.0.0.1:30572.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2020-16171?

It affects 1 product.


Products: Acronis Cyber Backup.

## How do I fix CVE-2020-16171?

No fix has been published for CVE-2020-16171 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-16171 being exploited?

There is no known exploitation of CVE-2020-16171 in the wild and no public exploit code.

Public exploit code:

- Acronis Cyber Backup 12.5 Build 16341 - Unauthenticated SSRF (exploitdb)

## Other vulnerabilities in n/a

- [CVE-2022-30995](https://insights.sbomify.com/CVE-2022-30995/): Information disclosure in Acronis Cyber Backup 12.5 (critical 9.3)
- [CVE-2022-3405](https://insights.sbomify.com/CVE-2022-3405/): Privilege escalation in Acronis Cyber Backup 12.5 (critical 9.3)
- [CVE-2020-10138](https://insights.sbomify.com/CVE-2020-10138/): Privilege escalation in Cyber Backup (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-16171 and fix it if it is affected.

What it is: CVE-2020-16171 is a medium-severity server-side request forgery vulnerability in n/a, published on 21 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-2020-16171 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-2020-16171/ (Markdown: https://insights.sbomify.com/CVE-2020-16171/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-16171
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-16171
- OSV: https://osv.dev/vulnerability/CVE-2020-16171

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-16171/
Summaries are generated and may contain mistakes; the official description above is the record.