---
title: "CVE-2018-5206\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2018-5206?format=md
keywords: index, follow
---

# CVE-2018-5206

Publication date 6 January 2018

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**9.8 · Critical**

[Score breakdown](https://ubuntu.com/security/CVE-2018-5206?format=md#impact-score)

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## Description

When the channel topic is set without specifying a sender, Irssi before
1.0.6 may dereference a NULL pointer.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2018-5206?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| irssi | 17.10 artful | Fixed 1.0.4-1ubuntu2.2 |
| 17.04 zesty | Fixed 0.8.20-2ubuntu2.3 |
| 16.04 LTS xenial | Fixed 0.8.19-1ubuntu1.6 |
| 14.04 LTS trusty | Fixed 0.8.15-5ubuntu3.4 |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2018-5206?format=md#patch-details)

## Notes

---

### [ratliff](https://launchpad.net/~ratliff)

GL#20, GL!25

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| irssi | * Upstream:   [7bed781](https://github.com/irssi/irssi/commit/7bed781622c8e336bc7c739109c0a07bf3a9c8e3) |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

9.8 · Critical

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | High |
  | Integrity impact | High |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 9.8 · Critical |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-5206)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-5206)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-5206)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2018-5206)

### Related Ubuntu Security Notices (USN)

+ [USN-3527-1](https://usn.ubuntu.com/USN-3527-1)
+ Irssi vulnerabilities
+ 10 January 2018

### Other references

* <https://irssi.org/security/irssi_sa_2018_01.txt>
* <https://github.com/irssi/irssi/releases/download/1.0.6/irssi-1.0.5_1.0.6.diff>
* <https://www.cve.org/CVERecord?id=CVE-2018-5206>