# CVE-2024-21742: Apache James Mime4J: Mime4J DOM header injection

> Attackers can inject unintended headers into MIME messages via improper input validation in the Apache James Mime4J library.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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:** Yes
- **Published:** 27 Feb 2024
- **Updated:** 6 May 2025
- **Also known as:** DEBIAN-CVE-2024-21742, GHSA-jw7r-rxff-gv24, OESA-2024-1333, OESA-2024-1475, OESA-2024-1476, OESA-2024-1477, OESA-2024-1478, OESA-2024-1479, RHLW-2026-0436667cee7724a6, RHLW-2026-e78d277bde69c3f5, UBUNTU-CVE-2024-21742

## What is CVE-2024-21742?

CVE-2024-21742 is a medium-severity vulnerability in Apache James Mime4J, published on 27 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper input validation allows for header injection in MIME4J library when using MIME4J DOM for composing message.
This can be exploited by an attacker to add unintended headers to MIME messages.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2024-21742?

2 open source packages ship an affected version, including org.apache.james:apache-mime4j-core. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.apache.james:apache-mime4j-core` | Maven | All versions | 0.8.10 |
| `org.apache.james:apache-mime4j-core` | Maven | All versions | 0.8.10 |

Products: Apache James Mime4j.

## How do I fix CVE-2024-21742?

Upgrade org.apache.james:apache-mime4j-core to 0.8.10 or later.

## Is CVE-2024-21742 being exploited?

There is no known exploitation of CVE-2024-21742 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-21742 and fix it if it is affected.

What it is: CVE-2024-21742 is a medium-severity vulnerability in Apache James Mime4J, published on 27 Feb 2024. 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-2024-21742 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.apache.james:apache-mime4j-core (Maven): affected all versions; fixed in 0.8.10
- org.apache.james:apache-mime4j-core (Maven): affected all versions; fixed in 0.8.10

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-2024-21742/ (Markdown: https://insights.sbomify.com/CVE-2024-21742/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21742
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21742
- OSV: https://osv.dev/vulnerability/CVE-2024-21742

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21742/
Summaries are generated and may contain mistakes; the official description above is the record.