# CVE-2009-0388: Integer overflow in n/a

> Remote VNC servers can trigger integer overflows in UltraVNC and TightVNC clients, causing crashes or arbitrary code execution.

- **Severity:** Critical 10.0 (`AV:N/AC:L/Au:N/C:C/I:C/A:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Feb 2009
- **Updated:** 7 Aug 2024
- **Also known as:** GHSA-j23w-r722-rm78

## What is CVE-2009-0388?

CVE-2009-0388 is a critical vulnerability in n/a, published on 4 Feb 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Multiple integer signedness errors in (1) UltraVNC 1.0.2 and 1.0.5 and (2) TightVnc 1.3.9 allow remote VNC servers to cause a denial of service (heap corruption and application crash) or possibly execute arbitrary code via a large length value in a message, related to the (a) ClientConnection::CheckBufferSize and (b) ClientConnection::CheckFileZipBufferSize functions in ClientConnection.cpp.

Weakness: CWE-189

## Which versions are affected by CVE-2009-0388?

It affects 2 products.


Products: Tightvnc Tightvnc, Ultravnc Ultravnc.

## How do I fix CVE-2009-0388?

No fix has been published for CVE-2009-0388 yet. Limit exposure of the affected software until one is available.

## Is CVE-2009-0388 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2009-0388 exists.

Public exploit code:

- UltraVNC/TightVNC (Multiple VNC Clients) - Multiple Integer Overflows (PoC) (exploitdb)
- TightVNC - Authentication Failure Integer Overflow (PoC) (exploitdb)

## Other vulnerabilities in n/a

- [CVE-2021-42785](https://insights.sbomify.com/CVE-2021-42785/): Buffer Overflow in tvnviewer.exe via Crafted Packet in TightVNC Viewer 2.8.59 (critical 9.8)
- [CVE-2019-15678](https://insights.sbomify.com/CVE-2019-15678/): Memory corruption in TightVNC (critical 9.8)
- [CVE-2019-15679](https://insights.sbomify.com/CVE-2019-15679/): Memory corruption in TightVNC (critical 9.8)
- [CVE-2019-8287](https://insights.sbomify.com/CVE-2019-8287/): Memory corruption in TightVNC (critical 9.8)
- [CVE-2023-27830](https://insights.sbomify.com/CVE-2023-27830/): Privilege escalation in n/a (critical 9.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2009-0388 and fix it if it is affected.

What it is: CVE-2009-0388 is a critical vulnerability in n/a, published on 4 Feb 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2009-0388 exists.

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-2009-0388/ (Markdown: https://insights.sbomify.com/CVE-2009-0388/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2009-0388
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2009-0388
- OSV: https://osv.dev/vulnerability/CVE-2009-0388

---
From sbomify Insights: https://insights.sbomify.com/CVE-2009-0388/
Summaries are generated and may contain mistakes; the official description above is the record.