CVE-2026-28389

Possible NULL Dereference When Processing CMS KeyAgreeRecipientInfo

Severity Score

7.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Attend

*SSVC

Descriptions

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.

*Credits: Nathan Sportsman (Praetorian), Daniel Rhea, Jaeho Nam (Seoul National University), Muhammad Daffa, Zhanpeng Liu (Tencent Xuanwu Lab), Guannan Wang (Tencent Xuanwu Lab), Guancheng Li (Tencent Xuanwu Lab), Joshua Rogers (Aisle Research), Neil Horman

CVSS Scores

CISAv3.1 7.5

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

* Common Vulnerability Scoring System

SSVC

Decision:Attend

Exploitation

None

Automatable

Yes

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2026-02-27 CVE Reserved
2026-04-07 CVE Published
2026-05-12 CVE Updated
2026-05-13 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-476: NULL Pointer Dereference

CAPEC

References (6)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC
https://github.com/openssl/openssl/commit/16cea4188e0ea567deb4f93f85902247e67384f5	2026-04-10
https://github.com/openssl/openssl/commit/785cbf7ea3b5a6f5adf0c1ccb92b79d89c35c616	2026-04-10
https://github.com/openssl/openssl/commit/7b5274e812400cacb6f3be4c2df5340923fa807f	2026-04-10
https://github.com/openssl/openssl/commit/c6725634e089eb2b634b10ede33944be7248172a	2026-04-10
https://github.com/openssl/openssl/commit/f80f83bc5fd036bc47d773e8b15a001e2b4ce686	2026-04-10

URL	Date	SRC
https://openssl-library.org/news/secadv/20260407.txt	2026-04-10

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
OpenSSL Search vendor "OpenSSL"		OpenSSL Search vendor "OpenSSL" for product "OpenSSL"				>= 3.6.0 < 3.6.2 Search vendor "OpenSSL" for product "OpenSSL" and version " >= 3.6.0 < 3.6.2"		en		Affected
OpenSSL Search vendor "OpenSSL"		OpenSSL Search vendor "OpenSSL" for product "OpenSSL"				>= 3.5.0 < 3.5.6 Search vendor "OpenSSL" for product "OpenSSL" and version " >= 3.5.0 < 3.5.6"		en		Affected
OpenSSL Search vendor "OpenSSL"		OpenSSL Search vendor "OpenSSL" for product "OpenSSL"				>= 3.4.0 < 3.4.5 Search vendor "OpenSSL" for product "OpenSSL" and version " >= 3.4.0 < 3.4.5"		en		Affected
OpenSSL Search vendor "OpenSSL"		OpenSSL Search vendor "OpenSSL" for product "OpenSSL"				>= 3.3.0 < 3.3.7 Search vendor "OpenSSL" for product "OpenSSL" and version " >= 3.3.0 < 3.3.7"		en		Affected
OpenSSL Search vendor "OpenSSL"		OpenSSL Search vendor "OpenSSL" for product "OpenSSL"				>= 3.0.0 < 3.0.20 Search vendor "OpenSSL" for product "OpenSSL" and version " >= 3.0.0 < 3.0.20"		en		Affected