# CVE-1999-1018: Security feature bypass in n/a

> Remote attackers can bypass IPChains firewall rules by sending fragmented packets, allowing unauthorized network access.

- **Severity:** High 7.5 (`AV:N/AC:L/Au:N/C:P/I:P/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Sep 2001
- **Updated:** 1 Aug 2024
- **Also known as:** GHSA-3xc5-vgfg-rqw3

## What is CVE-1999-1018?

CVE-1999-1018 is a high-severity vulnerability in Linux kernel, published on 12 Sep 2001. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

IPChains in Linux kernels 2.2.10 and earlier does not reassemble IP fragments before checking the header information, which allows a remote attacker to bypass the filtering rules using several fragments with 0 offsets.

## Which versions are affected by CVE-1999-1018?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-1999-1018?

No fix has been published for CVE-1999-1018 yet. Limit exposure of the affected software until one is available.

## Is CVE-1999-1018 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-1999-1018 exists.

Public exploit code:

- Linux Kernel 2.0.33 - IP Fragment Overlap (exploitdb)

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-1999-1018 and fix it if it is affected.

What it is: CVE-1999-1018 is a high-severity vulnerability in Linux kernel, published on 12 Sep 2001. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-1999-1018 exists.

Affected product: Linux kernel. 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-1999-1018/ (Markdown: https://insights.sbomify.com/CVE-1999-1018/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-1999-1018
- NVD: https://nvd.nist.gov/vuln/detail/CVE-1999-1018
- OSV: https://osv.dev/vulnerability/CVE-1999-1018

---
From sbomify Insights: https://insights.sbomify.com/CVE-1999-1018/
Summaries are generated and may contain mistakes; the official description above is the record.