# CVE-2020-12819: Memory corruption in FortiOS

> Remote attackers with valid SSL VPN credentials can crash the SSL VPN daemon via heap overflow in LCP processing when tunnel mode is enabled.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L/E:U/RL:X/RC:X`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Dec 2024
- **Updated:** 20 Dec 2024
- **Also known as:** GHSA-8vr7-33jp-gfgw

## What is CVE-2020-12819?

CVE-2020-12819 is a medium-severity memory corruption vulnerability in Fortinet Fortios, published on 19 Dec 2024. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A heap-based buffer overflow vulnerability in the processing of Link Control Protocol messages in FortiGate versions 5.6.12, 6.0.10, 6.2.4 and 6.4.1 and earlier may allow a remote attacker with valid SSL VPN credentials to crash the SSL VPN daemon by sending a large LCP packet, when tunnel mode is enabled. Arbitrary code execution may be theoretically possible, albeit practically very difficult to achieve in this context

Weakness: CWE-787 (Out-of-bounds Write), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2020-12819?

It affects 1 product.


Products: Fortinet Fortios.

## How do I fix CVE-2020-12819?

No fix has been published for CVE-2020-12819 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-12819 being exploited?

There is no known exploitation of CVE-2020-12819 in the wild and no public exploit code.

## Other vulnerabilities in Fortinet Fortios

- [CVE-2024-23113](https://insights.sbomify.com/CVE-2024-23113/): Fortinet Multiple Products Format String (critical 9.8, exploited in the wild)
- [CVE-2022-40684](https://insights.sbomify.com/CVE-2022-40684/): Fortinet Multiple Products Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2024-55591](https://insights.sbomify.com/CVE-2024-55591/): Fortinet FortiOS and FortiProxy Authentication Bypass (critical 9.6, exploited in the wild)
- [CVE-2024-21762](https://insights.sbomify.com/CVE-2024-21762/): Fortinet FortiOS Out-of-Bound Write (critical 9.6, exploited in the wild)
- [CVE-2022-42475](https://insights.sbomify.com/CVE-2022-42475/): Fortinet FortiOS Heap-Based Buffer Overflow (critical 9.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-12819 and fix it if it is affected.

What it is: CVE-2020-12819 is a medium-severity memory corruption vulnerability in Fortinet Fortios, published on 19 Dec 2024. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-12819 in the wild and no public exploit code.

Affected product: Fortinet Fortios. 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-2020-12819/ (Markdown: https://insights.sbomify.com/CVE-2020-12819/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-12819
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-12819
- OSV: https://osv.dev/vulnerability/CVE-2020-12819

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-12819/
Summaries are generated and may contain mistakes; the official description above is the record.