CVE-2023-6237

Description

Issue summary: Checking excessively long invalid RSA public keys may take a long time. Impact summary: Applications that use the function EVP_PKEY_public_check() to check RSA public keys may experience long delays. Where the key that is being checked has been obtained from an untrusted source this may lead to a Denial of Service. When function EVP_PKEY_public_check() is called on 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 an overly large prime, then this computation would take 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. The function EVP_PKEY_public_check() is not called from other OpenSSL functions however it is called from the OpenSSL pkey command line application. For that reason that application is also vulnerable if used with the '-pubin' and '-check' options on untrusted data. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are affected by this issue.

How to fix CVE-2023-6237

To remediate CVE-2023-6237, upgrade the affected package to a fixed version below.

• —upgrade to 3.0.12-r3 or later
• —upgrade to 3.0.13-1~deb12u1 or later

Is CVE-2023-6237 being exploited?

Low — EPSS is 0.9%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 3.0.12-r3
• from 0, < 3.0.13-1~deb12u1

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2023-6237
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2023-6237