========================================================================== 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
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