openssl, openssl1.0 vulnerabilities

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)