# CVE-2021-27931: XML external entity in n/a

> Unauthenticated attackers can exploit blind XXE in LumisXP to read local server files or cause denial of service via crafted API requests.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Mar 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-2rf2-p79x-79wj

## What is CVE-2021-27931?

CVE-2021-27931 is a critical vulnerability in n/a, published on 3 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

LumisXP (aka Lumis Experience Platform) before 10.0.0 allows unauthenticated blind XXE via an API request to PageControllerXml.jsp. One can send a request crafted with an XXE payload and achieve outcomes such as reading local server files or denial of service.

Weakness: CWE-611 (Improper Restriction of XML External Entity Reference)

## Which versions are affected by CVE-2021-27931?

It affects 1 product.


Products: Lumis Lumis Experience Platform.

## How do I fix CVE-2021-27931?

No fix has been published for CVE-2021-27931 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-27931 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-27931 exists.

Public exploit code:

- LumisXP <10.0.0 - Blind XML External Entity Attack (nuclei): http/cves/2021/CVE-2021-27931.yaml

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27931 and fix it if it is affected.

What it is: CVE-2021-27931 is a critical vulnerability in n/a, published on 3 Mar 2021. 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-2021-27931 exists.

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-2021-27931/ (Markdown: https://insights.sbomify.com/CVE-2021-27931/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27931
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27931
- OSV: https://osv.dev/vulnerability/CVE-2021-27931

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27931/
Summaries are generated and may contain mistakes; the official description above is the record.