SB2026042124 - Fedora 43 update for openssl
Published: April 21, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 secuirty vulnerabilities.
1) Always-Incorrect Control Flow Implementation (CVE-ID: CVE-2026-2673)
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.
2) NULL pointer dereference (CVE-ID: CVE-2026-28390)
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to NULL pointer dereference in CMS KeyTransportRecipientInfo processing when processing a crafted CMS EnvelopedData message using RSA-OAEP with a missing optional parameters field. A remote attacker can send a crafted CMS message to cause a denial of service.
Applications and services that call CMS_decrypt() on untrusted input, such as S/MIME processing or CMS-based protocols, are affected.
Remediation
Install update from vendor's website.