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.
Published: 2026-04-07
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

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Tracking

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Advisories
Source ID Title
Debian DSA Debian DSA DSA-6201-1 openssl security update
History

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

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: openssl

Published:

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

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

Link: CVE-2026-28389

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

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

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

Link: CVE-2026-28389

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses