An OpenSSL security update has been released for Ubuntu Linux 18.04 LTS, 20.04 LTS, and 21.04.

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Ubuntu Security Notice USN-5051-1
August 24, 2021

openssl vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 21.04
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in OpenSSL.

Software Description:
- openssl: Secure Socket Layer (SSL) cryptographic library and tools

Details:

John Ouyang discovered that OpenSSL incorrectly handled decrypting SM2
data. A remote attacker could use this issue to cause applications using
OpenSSL to crash, resulting in a denial of service, or possibly change
application behaviour. (CVE-2021-3711)

Ingo Schwarze discovered that OpenSSL incorrectly handled certain ASN.1
strings. A remote attacker could use this issue to cause OpenSSL to crash,
resulting in a denial of service, or possibly obtain sensitive information.
(CVE-2021-3712)

Update instructions:

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

Ubuntu 21.04:
libssl1.1 1.1.1j-1ubuntu3.5

Ubuntu 20.04 LTS:
libssl1.1 1.1.1f-1ubuntu2.8

Ubuntu 18.04 LTS:
libssl1.1 1.1.1-1ubuntu2.1~18.04.13

After a standard system update you need to reboot your computer to make
all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-5051-1
CVE-2021-3711, CVE-2021-3712

Package Information:
  https://launchpad.net/ubuntu/+source/openssl/1.1.1j-1ubuntu3.5
  https://launchpad.net/ubuntu/+source/openssl/1.1.1f-1ubuntu2.8
  https://launchpad.net/ubuntu/+source/openssl/1.1.1-1ubuntu2.1~18.04.13