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CVE-2026-28389

HIGHCVSS 7.5/10EPSS 1.03%

Last modified

CVE-2026-28389 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 1.03% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.5/10

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

EPSS Probability
1.03%

60.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
OpensslOpenssl>= 1.0.2, < 1.0.2zp
OpensslOpenssl>= 1.1.1, < 1.1.1zg
OpensslOpenssl>= 3.0.0, < 3.0.20
OpensslOpenssl>= 3.3.0, < 3.3.7
OpensslOpenssl>= 3.4.0, < 3.4.5
OpensslOpenssl>= 3.5.0, < 3.5.6
OpensslOpenssl>= 3.6.0, < 3.6.2

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2026-28389?
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.
How severe is CVE-2026-28389?
CVE-2026-28389 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.03% probability of exploitation in the next 30 days.
How do I fix CVE-2026-28389?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST