Always-Incorrect Control Flow Implementation in OpenSSL - CVE-2026-2673

Vulnerability identifier: #VU125561

CSH Severity: Low

CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-2673

CWE-ID: CWE-670

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause the use of a less preferred key agreement group.

The vulnerability exists due to improper implementation of group tuple handling in TLS 1.3 server key exchange group negotiation when processing a ClientHello with initial predicted keyshares while the server configuration uses the "DEFAULT" keyword. A remote attacker can send a crafted TLS handshake to cause the use of a less preferred key agreement group.

No OpenSSL FIPS modules are affected because the vulnerable code lies outside the FIPS boundary.

OpenSSL
Debian Linux
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Desktop 15
Ubuntu
Basesystem Module
Web and Scripting Module
Fedora
IBM MQ for HPE NonStop
openssl (Ubuntu package)
openssl (Debian package)
libopenssl-fips-provider
libopenssl-devel
openssl
libopenssl3
openssl-3-debugsource
libopenssl-3-fips-provider
openssl-3-debuginfo
libopenssl-3-fips-provider-debuginfo
libopenssl-3-devel
openssl-3
libopenssl3-debuginfo
libopenssl3-32bit-debuginfo
libopenssl-3-fips-provider-32bit
libopenssl3-32bit
libopenssl-3-fips-provider-32bit-debuginfo
nodejs24-docs
nodejs24-debuginfo
npm24
nodejs24
nodejs24-debugsource
nodejs24-devel

Install security update from vendor's website.

OpenSSL - addressed in versions 3.5.6, 3.6.2
IBM MQ for HPE NonStop - update to 8.1.0.40
openssl (Ubuntu package) - addressed in versions 1.0.1f-1ubuntu2.27+esm13, 1.0.2g-1ubuntu4.20+esm15, 1.0.2n-1ubuntu5.13+esm4, 1.1.1f-1ubuntu2.24+esm3, 1.1.1-1ubuntu2.1~18.04.23+esm8, 3.0.2-0ubuntu1.23, 3.0.13-0ubuntu3.9, 3.5.3-1ubuntu3.3
openssl (Debian package) - addressed in versions 3.0.19-1~deb12u2, 3.5.5-1~deb13u2
libopenssl-fips-provider - update to 3.5.0-150700.3.4.1
libopenssl-devel - update to 3.5.0-150700.3.4.1
openssl - update to 3.5.0-150700.3.4.1
libopenssl3 - update to 3.5.0-150700.5.45.2
openssl-3-debugsource - update to 3.5.0-150700.5.45.2
libopenssl-3-fips-provider - update to 3.5.0-150700.5.45.2
openssl-3-debuginfo - update to 3.5.0-150700.5.45.2
libopenssl-3-fips-provider-debuginfo - update to 3.5.0-150700.5.45.2
libopenssl-3-devel - update to 3.5.0-150700.5.45.2
openssl-3 - update to 3.5.0-150700.5.45.2
libopenssl3-debuginfo - update to 3.5.0-150700.5.45.2
libopenssl3-32bit-debuginfo - update to 3.5.0-150700.5.45.2
libopenssl-3-fips-provider-32bit - update to 3.5.0-150700.5.45.2
libopenssl3-32bit - update to 3.5.0-150700.5.45.2
libopenssl-3-fips-provider-32bit-debuginfo - update to 3.5.0-150700.5.45.2
openssl - addressed in versions 3.5.4-3.fc43, 3.5.5-2.fc44
nodejs24-docs - update to 24.18.1-150700.15.18.1
nodejs24-debuginfo - update to 24.18.1-150700.15.18.1
npm24 - update to 24.18.1-150700.15.18.1
nodejs24 - update to 24.18.1-150700.15.18.1
nodejs24-debugsource - update to 24.18.1-150700.15.18.1
nodejs24-devel - update to 24.18.1-150700.15.18.1

• https://openssl-library.org/news/secadv/20260313.txt

• Multiple vulnerabilities in OpenSSL
• Debian update for openssl
• Ubuntu update for openssl
• Ubuntu update for openssl
• Fedora 44 update for openssl
• Fedora 43 update for openssl
• Multiple vulnerabilities in IBM MQ for HPE NonStop
• SUSE update for openssl, openssl-3