OpenSSL Patches High-Severity Vulnerability Found With AI
OpenSSL patches 18 vulnerabilities, including a high-severity flaw potentially found by AI.
Summary
OpenSSL has released updates patching 18 vulnerabilities, with one high-severity flaw (CVE-2026-45447) identified as a user-after-free bug in PKCS#7 verification. This vulnerability, potentially discovered with the assistance of AI tools like Claude AI and Anthropic's Mythos model, could lead to remote code execution. Several other medium and low-severity vulnerabilities were also addressed, impacting decryption, integrity validation, and authentication mechanisms.
Full text
The latest OpenSSL releases patch 18 vulnerabilities, including a high-severity issue that could allow remote code execution. The high-severity vulnerability, tracked as CVE-2026-45447, is a heap user-after-free bug in a function used for PKCS#7 (Public-Key Cryptography Standard #7) verification. Discovered by a Calif researcher in collaboration with Claude AI and Anthropic Research, the bug can be triggered using a specially crafted PKCS#7 or S/MIME signed message during PKCS#7 signature verification. “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,” OpenSSL developers explained. Exploitation of the vulnerability can result in heap corruption, process crashes, and possibly in remote code execution. The moderate-severity flaws patched in OpenSSL can be exploited to decrypt encrypted communications, forge arbitrary ciphertexts, launch DoS attacks, bypass integrity validation, and execute arbitrary code. Advertisement. Scroll to continue reading. One of the medium-severity weaknesses can be exploited to trick a system into accepting a fake, attacker-controlled certificate and private key, allowing the attacker to bypass authentication mechanisms with a 1-in-256 success rate. The low-severity vulnerabilities can lead to crashes (DoS), message forgery, recovery of private keys, replacement of root CA certificates, and possibly arbitrary code execution. Alex Gaynor of Anthropic has been credited with reporting half a dozen of the newly patched vulnerabilities, suggesting that the AI giant’s Mythos model may have helped identify the flaws. High-severity vulnerabilities in OpenSSL are rare these days. Only one high-severity issue was patched last year, and CVE-2026-45447 is the second high-severity flaw of 2026. In April, OpenSSL developers patched a flaw that can allow an attacker to obtain sensitive data. Related: Drupal Patches Highly Critical Vulnerability Exposing Websites to Hacking Related: Google Patches 5th Chrome Zero-Day Exploited in 2026 Related: Android Update Patches Exploited Zero-Day, 123 Other Vulnerabilities Related: Oracle’s First Monthly Patches Resolve 77 Vulnerabilities Written By Eduard Kovacs Eduard Kovacs (@EduardKovacs) is senior managing editor at SecurityWeek. He worked as a high school IT teacher before starting a career in journalism in 2011. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering. Daily Briefing Newsletter Subscribe to the SecurityWeek Email Briefing for the latest cybersecurity threats, trends, and expert insights. 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Indicators of Compromise
- cve — CVE-2026-45447