# CVE-2021-29943: Apache Solr Unprivileged users may be able to perform unauthorized read/write to collections

> Unprivileged users can perform unauthorized read/write operations on collections when using specific authentication plugins due to credential forwarding errors.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** BIT-solr-2021-29943, GHSA-vf7p-j8x6-xvwp, UBUNTU-CVE-2021-29943

## What is CVE-2021-29943?

CVE-2021-29943 is a critical missing authorization vulnerability in Apache Solr, published on 13 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

When using ConfigurableInternodeAuthHadoopPlugin for authentication, Apache Solr versions prior to 8.8.2 would forward/proxy distributed requests using server credentials instead of original client credentials. This would result in incorrect authorization resolution on the receiving hosts.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2021-29943?

3 open source packages ship an affected version, including org.apache.solr:solr-parent and solr. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.apache.solr:solr-parent` | Maven | All versions | 8.8.2 |
| `org.apache.solr:solr-parent` | Maven | All versions | 8.8.2 |
| `solr` | Bitnami | All versions | 8.8.2 |

Products: Apache Solr.

## How do I fix CVE-2021-29943?

Upgrade org.apache.solr:solr-parent to 8.8.2 or later.

## Is CVE-2021-29943 being exploited?

There is no known exploitation of CVE-2021-29943 in the wild and no public exploit code.

## Other vulnerabilities in Apache Solr

- [CVE-2019-17558](https://insights.sbomify.com/CVE-2019-17558/): Apache Solr VelocityResponseWriter Plug-In Remote Code Execution (high 7.5, exploited in the wild)
- [CVE-2019-0193](https://insights.sbomify.com/CVE-2019-0193/): Apache Solr DataImportHandler Code Injection (high 7.2, exploited in the wild)
- [CVE-2024-45216](https://insights.sbomify.com/CVE-2024-45216/): Apache Solr: Authentication bypass possible using a fake URL Path ending (critical 9.8)
- [CVE-2021-44548](https://insights.sbomify.com/CVE-2021-44548/): Apache Solr information disclosure vulnerability through DataImportHandler (critical 9.8)
- [CVE-2021-27905](https://insights.sbomify.com/CVE-2021-27905/): SSRF vulnerability with the Replication handler (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-29943 and fix it if it is affected.

What it is: CVE-2021-29943 is a critical missing authorization vulnerability in Apache Solr, published on 13 Apr 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-2021-29943 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.apache.solr:solr-parent (Maven): affected all versions; fixed in 8.8.2
- org.apache.solr:solr-parent (Maven): affected all versions; fixed in 8.8.2
- solr (Bitnami): affected all versions; fixed in 8.8.2

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-2021-29943/ (Markdown: https://insights.sbomify.com/CVE-2021-29943/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-29943
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-29943
- OSV: https://osv.dev/vulnerability/CVE-2021-29943

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-29943/
Summaries are generated and may contain mistakes; the official description above is the record.