# CVE-2009-4355: Denial of service in n/a

> Remote attackers can cause denial of service via memory consumption in OpenSSL's zlib compression handling, affecting systems using SSL/TLS.

- **Severity:** Medium 5.0 (`AV:N/AC:L/Au:N/C:N/I:N/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Jan 2010
- **Updated:** 7 Aug 2024
- **Also known as:** DEBIAN-CVE-2009-4355, DSA-1970-1, GHSA-cg3r-vf2p-3f9h

## What is CVE-2009-4355?

CVE-2009-4355 is a medium-severity denial of service vulnerability in Openssl Openssl, published on 14 Jan 2010. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Memory leak in the zlib_stateful_finish function in crypto/comp/c_zlib.c in OpenSSL 0.9.8l and earlier and 1.0.0 Beta through Beta 4 allows remote attackers to cause a denial of service (memory consumption) via vectors that trigger incorrect calls to the CRYPTO_cleanup_all_ex_data function, as demonstrated by use of SSLv3 and PHP with the Apache HTTP Server, a related issue to CVE-2008-1678.

Weakness: CWE-399

## Which versions are affected by CVE-2009-4355?

It affects 2 products.


Products: Openssl Openssl, Redhat Openssl.

## How do I fix CVE-2009-4355?

Upgrade to a fixed version.

## Is CVE-2009-4355 being exploited?

There is no known exploitation of CVE-2009-4355 in the wild and no public exploit code.

## Other vulnerabilities in Openssl Openssl

- [CVE-2009-3245](https://insights.sbomify.com/CVE-2009-3245/): Null dereference in n/a (critical 10.0)
- [CVE-2006-3738](https://insights.sbomify.com/CVE-2006-3738/): Memory corruption in n/a (critical 10.0)
- [CVE-2026-63073](https://insights.sbomify.com/CVE-2026-63073/): Untrusted Sender DN Used as Format String in CMP Response Validation (critical 9.8)
- [CVE-2016-6309](https://insights.sbomify.com/CVE-2016-6309/): Use after free in n/a (critical 9.8)
- [CVE-2016-0799](https://insights.sbomify.com/CVE-2016-0799/): Integer overflow in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2009-4355 and fix it if it is affected.

What it is: CVE-2009-4355 is a medium-severity denial of service vulnerability in Openssl Openssl, published on 14 Jan 2010. 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-2009-4355 in the wild and no public exploit code.

Affected product: Openssl Openssl. 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-2009-4355/ (Markdown: https://insights.sbomify.com/CVE-2009-4355/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2009-4355
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2009-4355
- OSV: https://osv.dev/vulnerability/CVE-2009-4355

---
From sbomify Insights: https://insights.sbomify.com/CVE-2009-4355/
Summaries are generated and may contain mistakes; the official description above is the record.