CVE-2026-45447
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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 PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#7 signature verification. Impact summary: A use-after-free may result in process crashes, heap corruption, or potentially remote code execution. When processing a PKCS#7 or S/MIME signed message, if the SignedData digestAlgorithms field is present as an empty ASN.1 SET, OpenSSL may incorrectly free a caller-owned BIO during PKCS7_verify(). A subsequent use of the BIO by the calling application results in a use-after-free condition. In the common case this occurs when the application later calls BIO_free() on the BIO originally passed to PKCS7_verify(). Depending on allocator behavior and application-specific BIO usage patterns, this may result in a crash or other memory corruption. In some application contexts this may potentially be exploitable for remote code execution. Applications that process PKCS#7 or S/MIME signed messages using OpenSSL PKCS#7 APIs may be affected. Applications using the CMS APIs for this processing are not 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
CVE-2026-45447
EUVD
EUVD-2026-35491
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
openssl openssl *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
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Executive Summary

This vulnerability occurs when OpenSSL processes a specially crafted PKCS#7 or S/MIME signed message. If the SignedData digestAlgorithms field is present as an empty ASN.1 SET, OpenSSL may incorrectly free a caller-owned BIO during the PKCS7_verify() function.

This incorrect freeing leads to a use-after-free condition, meaning the application might later use memory that has already been freed, causing instability.

In practical terms, this happens when the application calls BIO_free() on the BIO originally passed to PKCS7_verify(), which may cause crashes, heap corruption, or potentially allow remote code execution depending on how memory is managed.

Applications using OpenSSL PKCS#7 APIs for processing signed messages are affected, but those using CMS APIs or the OpenSSL FIPS modules are not.

Impact Analysis

The vulnerability can lead to process crashes and heap corruption, which can cause denial of service or instability in applications processing PKCS#7 or S/MIME signed messages.

More seriously, in some application contexts, this use-after-free condition may be exploited to achieve remote code execution, allowing an attacker to run arbitrary code on the affected system.

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