# CVE-2021-47755: Oliver Library Server v5 - Arbitrary File Download

> Unauthenticated attackers can download arbitrary system files from Oliver Library Server v5 by manipulating the fileName parameter in the FileServlet endpoint.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Jan 2026
- **Updated:** 7 Apr 2026
- **Also known as:** GHSA-c22c-g99c-vw87

## What is CVE-2021-47755?

CVE-2021-47755 is a high-severity path traversal vulnerability in Softlink Education Oliver Library Server, published on 15 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Oliver Library Server v5 contains a file download vulnerability that allows unauthenticated attackers to access arbitrary system files through unsanitized input in the FileServlet endpoint. Attackers can exploit the vulnerability by manipulating the 'fileName' parameter to download sensitive files from the server's filesystem.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2021-47755?

It affects 1 product.


Products: Softlinkint Oliver V5 Library.

## How do I fix CVE-2021-47755?

No fix has been published for CVE-2021-47755 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-47755 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47755 exists.

## Other vulnerabilities in Softlink Education Oliver Library Server

- [CVE-2021-45027](https://insights.sbomify.com/CVE-2021-45027/): Path traversal in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-47755 and fix it if it is affected.

What it is: CVE-2021-47755 is a high-severity path traversal vulnerability in Softlink Education Oliver Library Server, published on 15 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47755 exists.

Affected product: Softlink Education Oliver Library Server. 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-2021-47755/ (Markdown: https://insights.sbomify.com/CVE-2021-47755/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47755
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47755
- OSV: https://osv.dev/vulnerability/CVE-2021-47755

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47755/
Summaries are generated and may contain mistakes; the official description above is the record.