USN-4738-1: OpenSSL vulnerabilities

Releases

• Ubuntu 20.10
• Ubuntu 20.04 LTS
• Ubuntu 18.04 ESM
• Ubuntu 16.04 ESM

Packages

• openssl - Secure Socket Layer (SSL) cryptographic library and tools
• openssl1.0 - Secure Socket Layer (SSL) cryptographic library and tools

Details

Paul Kehrer discovered that OpenSSL incorrectly handled certain input
lengths in EVP functions. A remote attacker could possibly use this issue
to cause OpenSSL to crash, resulting in a denial of service.
(CVE-2021-23840)

Tavis Ormandy discovered that OpenSSL incorrectly handled parsing issuer
fields. A remote attacker could possibly use this issue to cause OpenSSL to
crash, resulting in a denial of service. (CVE-2021-23841)

Update instructions

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

Ubuntu 20.10

• libssl1.1 - 1.1.1f-1ubuntu4.2

Ubuntu 20.04

• libssl1.1 - 1.1.1f-1ubuntu2.2

Ubuntu 18.04

• libssl1.0.0 - 1.0.2n-1ubuntu5.6
• libssl1.1 - 1.1.1-1ubuntu2.1~18.04.8

Ubuntu 16.04

• libssl1.0.0 - 1.0.2g-1ubuntu4.19

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

References

• CVE-2021-23841
• CVE-2021-23840

Related notices

• USN-4745-1
• USN-5088-1
• USN-7018-1