CVE-2026-42766
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BaseFortify

Publication date: 2026-06-09

Last updated on: 2026-06-09

Assigner: OpenSSL Software Foundation

Description
Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption. Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service. The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present. An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service. Applications that process password-encrypted CMS messages may be affected. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.
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Meta Information
Published
2026-06-09
Last Modified
2026-06-09
Generated
2026-06-10
AI Q&A
2026-06-09
EPSS Evaluated
N/A
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
openssl openssl to 4.0|end_excluding=3.6|end_excluding=3.5|end_excluding=3.4|end_excluding=3.0 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-476 The product dereferences a pointer that it expects to be valid but is NULL.
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Executive Summary

This vulnerability occurs when a specially crafted password-encrypted CMS message triggers a NULL pointer dereference during CMS decryption in OpenSSL.

The issue arises because the CMS PasswordRecipientInfo.keyDerivationAlgorithm field is optional and may be missing in some inputs, but the OpenSSL CMS implementation attempts to dereference this field without checking if it is present.

As a result, an attacker can supply such a crafted CMS message to cause the application to crash.

Impact Analysis

The primary impact of this vulnerability is that it can cause an application crash, leading to a Denial of Service (DoS).

Any application that processes password-encrypted CMS messages using the affected OpenSSL CMS implementation may be vulnerable to this crash.

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