# CVE-2019-3973: Memory corruption in Comodo Antivirus

> A local attacker can trigger a kernel crash or potentially execute code via an out-of-bounds write in the CmdGuard.sys driver.

- **Severity:** Medium 5.5 (`CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Jul 2019
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-mpmv-49pr-6hch

## What is CVE-2019-3973?

CVE-2019-3973 is a medium-severity memory corruption vulnerability in Comodo Antivirus, published on 17 Jul 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Comodo Antivirus versions 11.0.0.6582 and below are vulnerable to Denial of Service affecting CmdGuard.sys via its filter port "cmdServicePort". A low privileged process can crash CmdVirth.exe to decrease the port's connection count followed by process hollowing a CmdVirth.exe instance with malicious code to obtain a handle to "cmdServicePort". Once this occurs, a specially crafted message can be sent to "cmdServicePort" using "FilterSendMessage" API. This can trigger an out-of-bounds write if lpOutBuffer parameter in FilterSendMessage API is near the end of specified buffer bounds. The crash occurs when the driver performs a memset operation which uses a size beyond the size of buffer specified, causing kernel crash.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2019-3973?

It affects 1 product.


Products: Comodo Antivirus.

## How do I fix CVE-2019-3973?

No fix has been published for CVE-2019-3973 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-3973 being exploited?

There is no known exploitation of CVE-2019-3973 in the wild and no public exploit code.

## Other vulnerabilities in Comodo Antivirus

- [CVE-2022-34008](https://insights.sbomify.com/CVE-2022-34008/): Privilege escalation in n/a (high 7.8)
- [CVE-2019-3969](https://insights.sbomify.com/CVE-2019-3969/): Privilege escalation in Comodo Antivirus (high 7.8)
- [CVE-2019-14270](https://insights.sbomify.com/CVE-2019-14270/): Privilege escalation in n/a (high 7.1)
- [CVE-2019-3970](https://insights.sbomify.com/CVE-2019-3970/): Missing authorization in Comodo Antivirus (medium 5.5)
- [CVE-2019-3971](https://insights.sbomify.com/CVE-2019-3971/): Null dereference in Comodo Antivirus (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-3973 and fix it if it is affected.

What it is: CVE-2019-3973 is a medium-severity memory corruption vulnerability in Comodo Antivirus, published on 17 Jul 2019. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-3973 in the wild and no public exploit code.

Affected product: Comodo Antivirus. 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-2019-3973/ (Markdown: https://insights.sbomify.com/CVE-2019-3973/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-3973
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-3973
- OSV: https://osv.dev/vulnerability/CVE-2019-3973

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-3973/
Summaries are generated and may contain mistakes; the official description above is the record.