# CVE-2006-4434: Use after free in n/a

> Remote attackers can cause a denial of service in Sendmail by triggering a use-after-free error via a long header line, though impact is disputed.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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:** Yes
- **Published:** 29 Aug 2006
- **Updated:** 7 Aug 2024
- **Also known as:** DEBIAN-CVE-2006-4434, DSA-1164, GHSA-535c-fwmj-7hhw

## What is CVE-2006-4434?

CVE-2006-4434 is a high-severity use after free vulnerability in n/a, published on 29 Aug 2006. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Use-after-free vulnerability in Sendmail before 8.13.8 allows remote attackers to cause a denial of service (crash) via a long "header line", which causes a previously freed variable to be referenced. NOTE: the original developer has disputed the severity of this issue, saying "The only denial of service that is possible here is to fill up the disk with core dumps if the OS actually generates different core dumps (which is unlikely)... the bug is in the shutdown code (finis()) which leads directly to exit(3), i.e., the process would terminate anyway, no mail delivery or receiption is affected."

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2006-4434?

It affects 1 product.


Products: Sendmail Sendmail.

## How do I fix CVE-2006-4434?

Upgrade to a fixed version.

## Is CVE-2006-4434 being exploited?

There is no known exploitation of CVE-2006-4434 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2007-2246](https://insights.sbomify.com/CVE-2007-2246/): Denial of service in n/a (high 7.8)
- [CVE-2006-0058](https://insights.sbomify.com/CVE-2006-0058/): Race condition in n/a (high 7.6)
- [CVE-2009-4565](https://insights.sbomify.com/CVE-2009-4565/): Security feature bypass in n/a (high 7.5)
- [CVE-2002-2261](https://insights.sbomify.com/CVE-2002-2261/): Security feature bypass in n/a (high 7.5)
- [CVE-1999-1592](https://insights.sbomify.com/CVE-1999-1592/): Other in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2006-4434 and fix it if it is affected.

What it is: CVE-2006-4434 is a high-severity use after free vulnerability in n/a, published on 29 Aug 2006. 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-2006-4434 in the wild and no public exploit code.

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-2006-4434/ (Markdown: https://insights.sbomify.com/CVE-2006-4434/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2006-4434
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2006-4434
- OSV: https://osv.dev/vulnerability/CVE-2006-4434

---
From sbomify Insights: https://insights.sbomify.com/CVE-2006-4434/
Summaries are generated and may contain mistakes; the official description above is the record.