USN-8155-1: OpenSSL vulnerabilities

Publication date

8 April 2026

Overview

Several security issues were fixed in OpenSSL.


Packages

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

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,...

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

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

Learn more about how to get the fixes.

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

Ubuntu Release Package Version
25.10 questing libssl3t64 –  3.5.3-1ubuntu3.3
openssl –  3.5.3-1ubuntu3.3
24.04 LTS noble libssl3t64 –  3.0.13-0ubuntu3.9
openssl –  3.0.13-0ubuntu3.9
22.04 LTS jammy libssl3 –  3.0.2-0ubuntu1.23
openssl –  3.0.2-0ubuntu1.23

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