Use-After-Free Issue in OpenSSL Affecting PKCS#7 Signing
CVE-2026-45447

8.8HIGH

Key Information:

Vendor: OpenSSL
Status: OpenSSL
Vendor: CVE Published:; 9 June 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-45447?

An issue exists whereby processing a specially crafted PKCS#7 or S/MIME signed message can trigger a use-after-free condition during signature verification, possibly leading to crashes or memory corruption. The vulnerability arises when the SignedData digestAlgorithms field is empty, causing OpenSSL to incorrectly manage memory. This flaw impacts applications using the PKCS#7 APIs but does not affect those utilizing the CMS APIs. It’s essential for organizations to evaluate their OpenSSL implementations to mitigate potential exploitation risks.

Affected Version(s)

OpenSSL 4.0.0 < 4.0.1

OpenSSL 3.6.0 < 3.6.3

OpenSSL 3.5.0 < 3.5.7

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-45447
Created by HORKimhab