CVE-2023-6237

A flaw was found in OpenSSL. When the EVP_PKEY_public_check() function is called in RSA public keys, a computation is done to confirm that the RSA modulus, n, is composite. For valid RSA keys, n is a product of two or more large primes and this computation completes quickly. However, if n is a large prime, this computation takes a long time. An application that calls EVP_PKEY_public_check() and supplies an RSA key obtained from an untrusted source could be vulnerable to a Denial of Service attack.

Red Hat Product Security rates the severity of this flaw as determined by the upstream OpenSSL security team.

The marked moderate issue in OpenSSL involves a flaw in the EVP_PKEY_public_check() function used for RSA public keys. When verifying keys, the computation to confirm the composite nature of the RSA modulus may take an extended time if the modulus is a large prime. This vulnerability could be exploited for a Denial of Service attack in applications using this function with RSA keys from untrusted sources. The severity is moderate as it requires specific conditions for exploitation and may not pose an immediate widespread threat.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.