[USN-8155-2] OpenSSL vulnerabilities

========================================================================== Ubuntu Security Notice USN-8155-2 April 09, 2026 openssl, openssl1.0 vulnerabilities ========================================================================== 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 OpenSSL. Software Description: - openssl: Secure Socket Layer (SSL) cryptographic library and tools - openssl1.0: Secure Socket Layer (SSL) cryptographic library and tools Details: USN-8155-1 fixed vulnerabilities in OpenSSL. This update provides the corresponding updates for CVE-2026-28387 for openssl in Ubuntu 20.04 LTS. CVE-2026-28388 for openssl and openssl1.0 in Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS, and CVE-2026-28389 and CVE-2026-28390 for openssl and openssl1.0 for Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. Original advisory details: Viktor Dukhovni discovered that OpenSSL incorrectly negotiated the expected preferred key exchange group when used as a TLS 1.3 server. This could result in a less preferred key exchange being used, contrary to expectations. This issue only affected Ubuntu 25.10. (CVE-2026-2673) Igor Morgenstern discovered that OpenSSL incorrectly handled certain memory operations when used as a DANE client. A remote attacker could use this issue to cause OpenSSL to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-28387) Igor Morgenstern discovered that OpenSSL incorrectly handled certain memory operations when processing a delta CRL. A remote attacker could possibly use this issue to cause OpenSSL to crash, resulting in a denial of service. (CVE-2026-28388) Nathan Sportsman, Daniel Rhea, and Jaeho Nam discovered that OpenSSL incorrectly handled certain memory operations when processing a crafted CMS EnvelopedData message with KeyAgreeRecipientInfo. A remote attacker could possibly use this issue to cause OpenSSL to crash, resulting in a denial of service. (CVE-2026-28389) Muhammad Daffa, Joshua Rogers, and Chanho Kim discovered that OpenSSL incorrectly handled processing of a crafted CMS EnvelopedData message with KeyTransportRecipientInfo. A remote attacker could possibly use this issue to cause OpenSSL to crash, resulting in a denial of service. (CVE-2026-28390) Quoc Tran discovered that OpenSSL incorrectly handled hexadecimal conversion on 32-bit platforms. A remote attacker could use this issue to cause OpenSSL to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-31789) Simo Sorce discovered that OpenSSL incorrectly handled failures in RSA KEM RSASVE Encapsulation. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-31790) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 20.04 LTS libssl1.1 1.1.1f-1ubuntu2.24+esm3 Available with Ubuntu Pro openssl 1.1.1f-1ubuntu2.24+esm3 Available with Ubuntu Pro Ubuntu 18.04 LTS libssl1.0.0 1.0.2n-1ubuntu5.13+esm4 Available with Ubuntu Pro libssl1.1 1.1.1-1ubuntu2.1~18.04.23+esm8 Available with Ubuntu Pro openssl 1.1.1-1ubuntu2.1~18.04.23+esm8 Available with Ubuntu Pro openssl1.0 1.0.2n-1ubuntu5.13+esm4 Available with Ubuntu Pro Ubuntu 16.04 LTS libssl1.0.0 1.0.2g-1ubuntu4.20+esm15 Available with Ubuntu Pro openssl 1.0.2g-1ubuntu4.20+esm15 Available with Ubuntu Pro Ubuntu 14.04 LTS libssl1.0.0 1.0.1f-1ubuntu2.27+esm13 Available with Ubuntu Pro openssl 1.0.1f-1ubuntu2.27+esm13 Available with Ubuntu Pro After a standard system update you need to reboot your computer to make all the necessary changes. References: https://ubuntu.com/security/notices/USN-8155-2 https://ubuntu.com/security/notices/USN-8155-1 CVE-2026-28387, CVE-2026-28388, CVE-2026-28389, CVE-2026-28390