# CVE-2008-4770: Memory corruption in n/a

> Remote VNC servers can execute arbitrary code on clients via crafted RFB protocol data in RealVNC VNC Viewer.

- **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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 16 Jan 2009
- **Updated:** 7 Aug 2024
- **Also known as:** DSA-1716-1, GHSA-88j9-g2xv-54vp, RHSA-2009:0261

## What is CVE-2008-4770?

CVE-2008-4770 is a critical memory corruption vulnerability in n/a, published on 16 Jan 2009. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

The CMsgReader::readRect function in the VNC Viewer component in RealVNC VNC Free Edition 4.0 through 4.1.2, Enterprise Edition E4.0 through E4.4.2, and Personal Edition P4.0 through P4.4.2 allows remote VNC servers to execute arbitrary code via crafted RFB protocol data, related to "encoding type."

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2008-4770?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `vnc` | Red Hat:enterprise_linux:3::as | All versions | 0:4.0-0.beta4.1.8 |
| `vnc-debuginfo` | Red Hat:enterprise_linux:3::as | All versions | 0:4.0-0.beta4.1.8 |
| `vnc-server` | Red Hat:enterprise_linux:3::as | All versions | 0:4.0-0.beta4.1.8 |
| `vnc` | Red Hat:enterprise_linux:3::desktop | All versions | 0:4.0-0.beta4.1.8 |
| `vnc-debuginfo` | Red Hat:enterprise_linux:3::desktop | All versions | 0:4.0-0.beta4.1.8 |
| `vnc-server` | Red Hat:enterprise_linux:3::desktop | All versions | 0:4.0-0.beta4.1.8 |
| `vnc` | Red Hat:enterprise_linux:3::es | All versions | 0:4.0-0.beta4.1.8 |
| `vnc-debuginfo` | Red Hat:enterprise_linux:3::es | All versions | 0:4.0-0.beta4.1.8 |
| `vnc-server` | Red Hat:enterprise_linux:3::es | All versions | 0:4.0-0.beta4.1.8 |
| `vnc` | Red Hat:enterprise_linux:3::ws | All versions | 0:4.0-0.beta4.1.8 |
| `vnc-debuginfo` | Red Hat:enterprise_linux:3::ws | All versions | 0:4.0-0.beta4.1.8 |
| `vnc-server` | Red Hat:enterprise_linux:3::ws | All versions | 0:4.0-0.beta4.1.8 |
| `vnc` | Red Hat:enterprise_linux:4::as | All versions | 0:4.0-12.el4_7.1 |
| `vnc-debuginfo` | Red Hat:enterprise_linux:4::as | All versions | 0:4.0-12.el4_7.1 |
| `vnc-server` | Red Hat:enterprise_linux:4::as | All versions | 0:4.0-12.el4_7.1 |
| `vnc` | Red Hat:enterprise_linux:4::desktop | All versions | 0:4.0-12.el4_7.1 |
| `vnc-debuginfo` | Red Hat:enterprise_linux:4::desktop | All versions | 0:4.0-12.el4_7.1 |
| `vnc-server` | Red Hat:enterprise_linux:4::desktop | All versions | 0:4.0-12.el4_7.1 |
| `vnc` | Red Hat:enterprise_linux:4::es | All versions | 0:4.0-12.el4_7.1 |
| `vnc-debuginfo` | Red Hat:enterprise_linux:4::es | All versions | 0:4.0-12.el4_7.1 |
| `vnc-server` | Red Hat:enterprise_linux:4::es | All versions | 0:4.0-12.el4_7.1 |
| `vnc` | Red Hat:enterprise_linux:4::ws | All versions | 0:4.0-12.el4_7.1 |
| `vnc-debuginfo` | Red Hat:enterprise_linux:4::ws | All versions | 0:4.0-12.el4_7.1 |
| `vnc-server` | Red Hat:enterprise_linux:4::ws | All versions | 0:4.0-12.el4_7.1 |
| `vnc` | Red Hat:enterprise_linux:5::client | All versions | 0:4.1.2-14.el5_3.1 |
| `vnc-debuginfo` | Red Hat:enterprise_linux:5::client | All versions | 0:4.1.2-14.el5_3.1 |
| `vnc-server` | Red Hat:enterprise_linux:5::client | All versions | 0:4.1.2-14.el5_3.1 |
| `vnc` | Red Hat:enterprise_linux:5::server | All versions | 0:4.1.2-14.el5_3.1 |
| `vnc-debuginfo` | Red Hat:enterprise_linux:5::server | All versions | 0:4.1.2-14.el5_3.1 |
| `vnc-server` | Red Hat:enterprise_linux:5::server | All versions | 0:4.1.2-14.el5_3.1 |

Products: Realvnc Realvnc.

## How do I fix CVE-2008-4770?

Upgrade to a fixed version.

## Is CVE-2008-4770 being exploited?

There is no known exploitation of CVE-2008-4770 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2013-6886](https://insights.sbomify.com/CVE-2013-6886/): Privilege escalation in n/a (high 7.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2008-4770 and fix it if it is affected.

What it is: CVE-2008-4770 is a critical memory corruption vulnerability in n/a, published on 16 Jan 2009. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2008-4770 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-2008-4770/ (Markdown: https://insights.sbomify.com/CVE-2008-4770/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2008-4770
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2008-4770
- OSV: https://osv.dev/vulnerability/CVE-2008-4770

---
From sbomify Insights: https://insights.sbomify.com/CVE-2008-4770/
Summaries are generated and may contain mistakes; the official description above is the record.