---
title: "CVE-2018-18508\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-2018-18508?format=md
keywords: index, follow
---

# CVE-2018-18508

Publication date 31 December 2018

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**6.5 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2018-18508?format=md#impact-score)

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## Description

In Network Security Services (NSS) before 3.36.7 and before 3.41.1, a
malformed signature can cause a crash due to a null dereference, resulting
in a Denial of Service.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2018-18508?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| nss | 18.10 cosmic | Fixed 2:3.36.1-1ubuntu1.2 |
| 18.04 LTS bionic | Fixed 2:3.35-2ubuntu2.2 |
| 16.04 LTS xenial | Fixed 2:3.28.4-0ubuntu0.16.04.5 |
| 14.04 LTS trusty | Fixed 2:3.28.4-0ubuntu0.14.04.5 |

---

* [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-2018-18508?format=md#patch-details)

## Notes

---

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

not included in 3.42, error in release notes

### 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 |
| --- | --- |
| nss | * Upstream:   <https://hg.mozilla.org/projects/nss/rev/08d1b0c1117f> * Upstream:   <https://hg.mozilla.org/projects/nss/rev/5e70b72131ac> |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

6.5 · Medium

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 6.5 · Medium |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-18508)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-18508)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-18508)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2018-18508)

### Related Ubuntu Security Notices (USN)

+ [USN-3898-1](https://usn.ubuntu.com/USN-3898-1)
+ NSS vulnerability
+ 27 February 2019

+ [USN-3898-2](https://usn.ubuntu.com/USN-3898-2)
+ NSS vulnerability
+ 27 February 2019

### Other references

* <https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.42.1_release_notes>
* <https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.41.1_release_notes>
* <https://www.cve.org/CVERecord?id=CVE-2018-18508>