# CVE-2019-18625: An issue was discovered in Suricata 5.0.0.


- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 6 Jan 2020
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-18625, GHSA-h726-j7j2-xhpf, UBUNTU-CVE-2019-18625

## What is CVE-2019-18625?

CVE-2019-18625 is a high-severity vulnerability in Debian Debian Linux, published on 6 Jan 2020. 

### Official description

An issue was discovered in Suricata 5.0.0. It was possible to bypass/evade any tcp based signature by faking a closed TCP session using an evil server. After the TCP SYN packet, it is possible to inject a RST ACK and a FIN ACK packet with a bad TCP Timestamp option. The client will ignore the RST ACK and the FIN ACK packets because of the bad TCP Timestamp option. Both linux and windows client are ignoring the injected packets.

## Which versions are affected by CVE-2019-18625?

It affects 2 products.


Products: Debian Debian Linux, Oisf Suricata.

## How do I fix CVE-2019-18625?

Upgrade to a fixed version.

## Is CVE-2019-18625 being exploited?

There is no known exploitation of CVE-2019-18625 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-18625 and fix it if it is affected.

What it is: CVE-2019-18625 is a high-severity vulnerability in Debian Debian Linux, published on 6 Jan 2020. 
Exploitation: There is no known exploitation of CVE-2019-18625 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2019-18625/ (Markdown: https://insights.sbomify.com/CVE-2019-18625/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-18625
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-18625
- OSV: https://osv.dev/vulnerability/CVE-2019-18625

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-18625/
Summaries are generated and may contain mistakes; the official description above is the record.