# CVE-2022-43501: Weak cryptography in Kasago IPv4

> Attackers can predict TCP Initial Sequence Numbers to hijack connections or spoof traffic in KASAGO TCP/IP stacks.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Feb 2023
- **Updated:** 24 Mar 2025
- **Also known as:** GHSA-96qq-9h7m-67pw

## What is CVE-2022-43501?

CVE-2022-43501 is a critical vulnerability in ZUKEN Elmic Kasago IPv4, published on 10 Feb 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

KASAGO TCP/IP stack provided by Zuken Elmic generates ISNs(Initial Sequence Number) for TCP connections from an insufficiently random source. An attacker may be able to determine the ISN of the current or future TCP connections and either hijack existing ones or spoof future ones.

Weakness: CWE-330 (Use of Insufficiently Random Values)

## Which versions are affected by CVE-2022-43501?

It affects 4 products.


Products: Elwsc Kasago Ipv4, Elwsc Kasago Ipv4 Light, Elwsc Kasago Ipv6\/V4 Dual, Elwsc Kasago Mobile Ipv6.

## How do I fix CVE-2022-43501?

No fix has been published for CVE-2022-43501 yet. Limit exposure of the affected software until one is available.

## Is CVE-2022-43501 being exploited?

There is no known exploitation of CVE-2022-43501 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-43501 and fix it if it is affected.

What it is: CVE-2022-43501 is a critical vulnerability in ZUKEN Elmic Kasago IPv4, published on 10 Feb 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2022-43501 in the wild and no public exploit code.

Affected product: ZUKEN Elmic Kasago IPv4. 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-2022-43501/ (Markdown: https://insights.sbomify.com/CVE-2022-43501/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-43501
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-43501
- OSV: https://osv.dev/vulnerability/CVE-2022-43501

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-43501/
Summaries are generated and may contain mistakes; the official description above is the record.