Heap Use-After-Free in OpenSSL PKCS7_verify()
CVE-2026-45447 is a high-severity use-after-free vulnerability in OpenSSL's PKCS#7 signature verification path. When an application processes a specially crafted PKCS#7 or S/MIME signed message via the PKCS#7 APIs, and the SignedData digestAlgorithms field is encoded as an empty ASN.1 SET, OpenSSL may incorrectly free a caller-owned BIO during PKCS7_verify(). If the application subsequently reuses or frees that BIO, a use-after-free condition occurs. In the common case, this is triggered when the caller later invokes BIO_free() on the same BIO originally passed to PKCS7_verify(). The issue affects applications using OpenSSL PKCS#7 APIs for PKCS#7 or S/MIME signed message verification; the CMS APIs are explicitly stated to be unaffected. Reported affected versions are OpenSSL 4.0.0 before 4.0.1, 3.6.0 before 3.6.3, 3.5.0 before 3.5.7, 3.4.0 before 3.4.6, 3.0.0 before 3.0.21, 1.1.1 before 1.1.1zh, and 1.0.2 before 1.0.2zq. The OpenSSL FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected because the vulnerable code is outside the FIPS module boundary.
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Recent activity
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A critical heap-based use-after-free/memory corruption vulnerability in OpenSSL PKCS#7/S/MIME signature verification routines that may lead to remote code execution or server disruption when crafted signed messages are processed.
A high-severity OpenSSL use-after-free in PKCS7_verify() triggered by crafted PKCS#7 or S/MIME signed messages, potentially causing crashes, heap corruption, or remote code execution.
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Cross-references every affected SKU, including bundled OEM variants.
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