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Review reviewHigh

CVE-2026-28390

OpenSSL OpenSSL, SIMATIC CN 4100, SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Issue summary: During processing of a crafted CMS EnvelopedData message with KeyTransportRecipientInfo 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 KeyTransportRecipientInfo with RSA-OAEP encryption is processed, the optional parameters field of RSA-OAEP SourceFunc algorithm identifier is examined without checking for its presence. This results in a NULL pointer dereference if the field i...

CVSS
7.5
EPSS
1.03%
60.3% percentile
CISA KEV
Not listed
Published
2026.04.08
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability1.03%
Technical severityCVSS 7.5

Vulnerability overview

Issue summary: During processing of a crafted CMS EnvelopedData message with KeyTransportRecipientInfo 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 KeyTransportRecipientInfo with RSA-OAEP encryption is processed, the optional parameters field of RSA-OAEP SourceFunc algorithm identifier is examined without checking for its presence. This results in a NULL pointer dereference if the field i...

Affected product and versions

Product
OpenSSL OpenSSL, SIMATIC CN 4100, SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
Affected versions
>= 3.6.0 < 3.6.2, >= 3.5.0 < 3.5.6, >= 3.4.0 < 3.4.5, >= 3.3.0 < 3.3.7, >= 3.0.0 < 3.0.20, >= 1.1.1 < 1.1.1zg, >= 1.0.2 < 1.0.2zp, < V5.0
Fixed versions
1.0.2zp, 1.1.1zg, 3.0.20, 3.3.7, 3.4.5, 3.5.6, 3.6.2

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that OpenSSL OpenSSL, SIMATIC CN 4100, SIMATIC S7-1500 TM MFP - GNU/Linux subsystem and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
CWE-476