Issue summary: During processing of a crafted CMS EnvelopedData message with KeyAgreeRecipientInfo a NULL pointer dereference can happen. Impact summary: Applications that process attacker-controlled CMS data may crash before authentication or cryptographic operations occur resulting in Denial of Service. When a CMS EnvelopedData message that uses KeyAgreeRecipientInfo is processed, the optional parameters field of KeyEncryptionAlgorithmIdentifier is examined without checking for its presence. This results in a NULL pointer dereference if the field is missing. Applications and services that call CMS_decrypt() on untrusted input (e.g., S/MIME processing or CMS-based protocols) are vulnerable. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.
History

Fri, 10 Apr 2026 21:15:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Fri, 10 Apr 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-166
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low


Wed, 08 Apr 2026 19:45:00 +0000

Type Values Removed Values Added
First Time appeared Openssl
Openssl openssl
Vendors & Products Openssl
Openssl openssl

Tue, 07 Apr 2026 22:15:00 +0000

Type Values Removed Values Added
Description Issue summary: During processing of a crafted CMS EnvelopedData message with KeyAgreeRecipientInfo a NULL pointer dereference can happen. Impact summary: Applications that process attacker-controlled CMS data may crash before authentication or cryptographic operations occur resulting in Denial of Service. When a CMS EnvelopedData message that uses KeyAgreeRecipientInfo is processed, the optional parameters field of KeyEncryptionAlgorithmIdentifier is examined without checking for its presence. This results in a NULL pointer dereference if the field is missing. Applications and services that call CMS_decrypt() on untrusted input (e.g., S/MIME processing or CMS-based protocols) are vulnerable. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.
Title Possible NULL Dereference When Processing CMS KeyAgreeRecipientInfo
Weaknesses CWE-476
References

cve-icon MITRE

Status: PUBLISHED

Assigner: openssl

Published: 2026-04-07T22:00:53.364Z

Updated: 2026-04-15T07:28:13.700Z

Reserved: 2026-02-27T13:45:02.161Z

Link: CVE-2026-28389

cve-icon Vulnrichment

Updated: 2026-04-10T20:20:40.423Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-04-07T22:16:21.030

Modified: 2026-04-10T21:16:23.410

Link: CVE-2026-28389

cve-icon Redhat

Severity : Low

Publid Date: 2026-04-07T00:00:00Z

Links: CVE-2026-28389 - Bugzilla