--- title: "CVE-2018-5382\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-2018-5382?format=md keywords: index, follow --- # CVE-2018-5382 Publication date 16 April 2018 Last updated 25 August 2025 --- Ubuntu priority **Medium** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) ## Cvss 3 Severity Score **4.4 · Medium** [Score breakdown](https://ubuntu.com/security/CVE-2018-5382?format=md#impact-score) Toggle side navigation ## Description The default BKS keystore use an HMAC that is only 16 bits long, which can allow an attacker to compromise the integrity of a BKS keystore. Bouncy Castle release 1.47 changes the BKS format to a format which uses a 160 bit HMAC instead. This applies to any BKS keystore generated prior to BC 1.47. For situations where people need to create the files for legacy reasons a specific keystore type "BKS-V1" was introduced in 1.49. It should be noted that the use of "BKS-V1" is discouraged by the library authors and should only be used where it is otherwise safe to do so, as in where the use of a 16 bit checksum for the file integrity check is not going to cause a security issue in itself. [Read the notes from the security team](https://ubuntu.com/security/CVE-2018-5382?format=md#notes) ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | | bouncycastle | 17.10 artful | Not affected | | 16.04 LTS xenial | Not affected | | 14.04 LTS trusty | Not in release | --- * [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) * [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses) ## Notes --- ### [mdeslaur](https://launchpad.net/~mdeslaur) fixed in 1.47 ## Severity score breakdown CVSS version: CVSS v3.0 **Base score** 4.4 · Medium * Base metrics | Parameter | Value | | --- | --- | | Attack vector | Local | | Attack complexity | Low | | Privileges required | Low | | User interaction | None | | Scope | Unchanged | | Confidentiality impact | Low | | Integrity impact | Low | | Availability impact | None | * Scores | Parameter | Value | | --- | --- | | Base score | 4.4 · Medium | | Exploitability score | - | | Impact score | - | **Vector:** CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-5382) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-5382) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-5382) * [Debian](https://security-tracker.debian.org/tracker/CVE-2018-5382) ### Other references * * *