Just as organizations were working to patch the Microsoft Office zero-day (CVE-2026-21509), the cybersecurity world is confronted with another serious threat. OpenSSL disclosed a high-severity stack buffer overflow issue that can trigger denial-of-service (DoS) conditions and, under specific circumstances, enable remote code execution (RCE).
Tracked as CVE-2025-15467, the vulnerability was promptly patched by the vendor alongside another 11 security bugs in the open source SSL/TLS toolkit.
OpenSSL is a widely used open-source library that powers SSL/TLS security across websites, VPNs, email servers, and apps worldwide, protecting data integrity and privacy. But with such widespread use comes the risk layer. The 2025 OSSRA Report states that 86% of commercial codebases contained open-source vulnerabilities, 81% of them high or critical.
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CVE-2025-15467 Analysis
According to the OpenSSL advisory released on January 27, CVE-2025-15467 impacts the handling of Cryptographic Message Syntax (CMS) AuthEnvelopedData structures within OpenSSL’s cryptographic library. Specifically, it arises from a stuck buffer overflow during the parsing of CMS AuthEnvelopedData when processing maliciously crafted AEAD parameters.
“When parsing CMS AuthEnvelopedData structures that use AEAD ciphers such as AES-GCM, the IV (Initialization Vector) encoded in the ASN.1 parameters is copied into a fixed-size stack buffer without verifying that its length fits the destination,” OpenSSL explains.
As a result, the flaw allows an attacker to supply a specially crafted CMS message with an oversized IV, causing a stack-based out-of-bounds write before any authentication or tag checks are performed.
Any application or service that processes untrusted CMS or PKCS#7 content with AEAD ciphers (such as S/MIME AuthEnvelopedData using AES-GCM) is at risk. The vulnerability is particularly concerning because the overflow occurs before authentication, meaning an attacker does not need valid key material to exploit it.
OpenSSL versions 3.0 through 3.6 are affected, while 1.1.1 and 1.0.2 remain safe. Users should update to the 3.6.1, 3.5.5, 3.4.4, 3.3.6, and 3.0.19 patched releases, depending on their version.
Notably, CVE-2025-15467 may be exploited to achieve remote code execution. While the success of such attacks depends on platform-specific conditions and compiler-level protections, the presence of a stack buffer overflow significantly lowers the barrier to exploitation, requiring immediate patching.
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The post CVE-2025-15467: OpenSSL Vulnerability Leads to Denial-of-Service, Remote Code Execution appeared first on SOC Prime.
