CVE-2026-22796

/// Technical description

Issue summary: A type confusion vulnerability exists in the signature

verification of signed PKCS#7 data where an ASN1_TYPE union member is

accessed without first validating the type, causing an invalid or NULL

pointer dereference when processing malformed PKCS#7 data.

Impact summary: An application performing signature verification of PKCS#7

data or calling directly the PKCS7_digest_from_attributes() function can be

caused to dereference an invalid or NULL pointer when reading, resulting in

a Denial of Service.

The function PKCS7_digest_from_attributes() accesses the message digest attribute

value without validating its type. When the type is not V_ASN1_OCTET_STRING,

this results in accessing invalid memory through the ASN1_TYPE union, causing

a crash.

Exploiting this vulnerability requires an attacker to provide a malformed

signed PKCS#7 to an application that verifies it. The impact of the

exploit is just a Denial of Service, the PKCS7 API is legacy and applications

should be usi

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References