---
title: "CVE-2017-9023\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-2017-9023?format=md
keywords: index, follow
---

# CVE-2017-9023

Publication date 30 May 2017

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**7.5 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2017-9023?format=md#impact-score)

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## Description

The ASN.1 parser in strongSwan before 5.5.3 improperly handles CHOICE types
when the x509 plugin is enabled, which allows remote attackers to cause a
denial of service (infinite loop) via a crafted certificate.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| strongswan | 17.04 zesty | Fixed 5.5.1-1ubuntu3.1 |
| 16.10 yakkety | Fixed 5.3.5-1ubuntu4.3 |
| 16.04 LTS xenial | Fixed 5.3.5-1ubuntu3.3 |
| 14.04 LTS trusty | Fixed 5.1.2-0ubuntu2.6 |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.5 · High

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.5 · High |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-9023)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2017-9023)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2017-9023)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2017-9023)

### Related Ubuntu Security Notices (USN)

+ [USN-3301-1](https://usn.ubuntu.com/USN-3301-1)
+ strongSwan vulnerabilities
+ 30 May 2017

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2017-9023>