[USN-7954-2] Libtasn1 vulnerabilities

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Ubuntu Security Notice USN-7954-2
February 10, 2026

libtasn1-6 vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in Libtasn1.

Software Description:
- libtasn1-6: Library to manage ASN.1 structures

Details:

USN-7954-1 fixed vulnerabilities in Libtasn1. This update provides the
corresponding updates for Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, Ubuntu
18.04 LTS, and Ubuntu 20.04 LTS. CVE-2021-46848 only affected Ubuntu
14.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS.

Original advisory details:

It was discovered that Libtasn1 incorrectly handled decoding ASN.1
content. An attacker could possibly use this issue to cause Libtasn1 to
crash, resulting in a denial of service. (CVE-2025-13151)

It was discovered that Libtasn1 incorrectly handled encoding ASN.1
content. An attacker could possibly use this issue to cause Libtasn1 to
crash, resulting in a denial of service. This issue only affected
Ubuntu 22.04 LTS. (CVE-2021-46848)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.04 LTS
libtasn1-6 4.16.0-2ubuntu0.1+esm1
Available with Ubuntu Pro

Ubuntu 18.04 LTS
libtasn1-6 4.13-2ubuntu0.1~esm1
Available with Ubuntu Pro

Ubuntu 16.04 LTS
libtasn1-6 4.7-3ubuntu0.16.04.3+esm4
Available with Ubuntu Pro

Ubuntu 14.04 LTS
libtasn1-6 3.4-3ubuntu0.6+esm1
Available with Ubuntu Pro

In general, a standard system update will make all the necessary changes.

References:
https://ubuntu.com/security/notices/USN-7954-2
https://ubuntu.com/security/notices/USN-7954-1
CVE-2021-46848, CVE-2025-13151