OpenSSL updates released on Tuesday patch a dozen vulnerabilities, including a high-severity remote code execution flaw.
All 12 vulnerabilities patched in the open source SSL/TLS toolkit were discovered by cybersecurity firm Aisle, which used an autonomous analyzer to identify the security holes.
The high-severity issue is tracked as CVE-2025-15467 and it has been described as a stack buffer overflow that could lead to a crash (DoS condition) or remote code execution in certain conditions.
OpenSSL maintainers explained in their advisory:
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. An attacker can supply a crafted CMS message with an oversized IV, causing a stack-based out-of-bounds write before any authentication or tag verification occurs.
Applications and services that parse untrusted CMS or PKCS#7 content using AEAD ciphers (e.g., S/MIME AuthEnvelopedData with AES-GCM) are vulnerable. Because the overflow occurs prior to authentication, no valid key material is required to trigger it. While exploitability to remote code execution depends on platform and toolchain mitigations, the stack-based write primitive represents a severe risk.
The latest OpenSSL releases also address CVE-2025-11187, a moderate-severity issue whose exploitation could also lead to a DoS condition or even remote code execution.
The remaining flaws have been classified as low severity. A majority of them can be exploited to cause a DoS condition, and a couple are related to authentication and information exposure.
Aisle pointed out that in addition to the 12 vulnerabilitites that have been assigned a CVE, it identified six issues that have been addressed prior to the affected code being included in a release.
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