Attack Chain

1. An attacker identifies an application using rust-openssl compiled against OpenSSL 1.1.1.
2. The attacker crafts a malicious input designed to trigger the Deriver::derive or PkeyCtxRef::derive functions.
3. The malicious input is sent to the vulnerable application.
4. The application processes the malicious input using Deriver::derive or PkeyCtxRef::derive.
5. Due to the insufficient buffer size validation within these functions, the input overflows the allocated buffer.
6. The buffer overflow corrupts adjacent memory regions, potentially overwriting critical data or code.
7. If the overflow overwrites code, the attacker could potentially execute arbitrary code within the context of the application.
8. Successful exploitation leads to either a denial-of-service (application crash) or arbitrary code execution, allowing the attacker to gain control of the system or application.

Impact

Successful exploitation of CVE-2026-41676 can lead to significant consequences, including denial-of-service, where the application becomes unresponsive or crashes. In a more severe scenario, an attacker could achieve arbitrary code execution, potentially gaining complete control over the affected system. This could lead to data breaches, system compromise, and further malicious activities. Given the widespread use of OpenSSL, a large number of systems are potentially vulnerable.

Recommendation

• Upgrade to a patched version of rust-openssl that addresses CVE-2026-41676.
• If upgrading rust-openssl is not immediately feasible, ensure that OpenSSL 1.1.1 is not in use. Consider upgrading to a newer, supported version of OpenSSL.
• Deploy the Sigma rules provided below to detect potential exploitation attempts targeting CVE-2026-41676.