# CVE-2021-40111: Apache James IMAP parsing Denial Of Service

> Authenticated attackers can cause denial of service in Apache James via crafted IMAP commands triggering infinite loops and memory exhaustion.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 4 Jan 2022
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-fqgw-6qj5-8hmp

## What is CVE-2021-40111?

CVE-2021-40111 is a medium-severity denial of service vulnerability in Apache James, published on 4 Jan 2022. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

In Apache James, while fuzzing with Jazzer the IMAP parsing stack, we discover that crafted APPEND and STATUS IMAP command could be used to trigger infinite loops resulting in expensive CPU computations and OutOfMemory exceptions. This can be used for a Denial Of Service attack. The IMAP user needs to be authenticated to exploit this vulnerability. This affected Apache James prior to version 3.6.1. This vulnerability had been patched in Apache James 3.6.1 and higher. We recommend the upgrade.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2021-40111?

2 open source packages ship an affected version, including org.apache.james:james-server. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.apache.james:james-server` | Maven | All versions | 3.6.1 |
| `org.apache.james:james-server` | Maven | All versions | 3.6.1 |

Products: Apache James.

## How do I fix CVE-2021-40111?

Upgrade org.apache.james:james-server to 3.6.1 or later.

## Is CVE-2021-40111 being exploited?

There is no known exploitation of CVE-2021-40111 in the wild and no public exploit code.

## Other vulnerabilities in Apache James

- [CVE-2023-51518](https://insights.sbomify.com/CVE-2023-51518/): Apache James server: Privilege escalation via JMX pre-authentication deserialisation (critical 9.8)
- [CVE-2019-0228](https://insights.sbomify.com/CVE-2019-0228/): Vulnerability that affects org.apache.pdfbox:pdfbox (critical 9.8)
- [CVE-2021-40525](https://insights.sbomify.com/CVE-2021-40525/): Sieve file storage vulnerable to path traversal attacks (critical 9.1)
- [CVE-2023-26269](https://insights.sbomify.com/CVE-2023-26269/): Apache James server: Privilege escalation through unauthenticated JMX (high 7.8)
- [CVE-2006-2806](https://insights.sbomify.com/CVE-2006-2806/): Denial of service in n/a (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-40111 and fix it if it is affected.

What it is: CVE-2021-40111 is a medium-severity denial of service vulnerability in Apache James, published on 4 Jan 2022. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-40111 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.apache.james:james-server (Maven): affected all versions; fixed in 3.6.1
- org.apache.james:james-server (Maven): affected all versions; fixed in 3.6.1

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-2021-40111/ (Markdown: https://insights.sbomify.com/CVE-2021-40111/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-40111
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-40111
- OSV: https://osv.dev/vulnerability/CVE-2021-40111

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-40111/
Summaries are generated and may contain mistakes; the official description above is the record.