Vulnerability in Openssl

CVE-2023-6237

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.

EPSS: 0.023 (81.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

  • Openssl — versions 3.0.0, 3.1.0, 3.2.0

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2023-6237?
CVE-2023-6237 is a medium-severity vulnerability in Openssl, classified under CWE-606. CVSS score: 5.9/10. Published 2024-04-25.
How severe is CVE-2023-6237?
Medium severity. CVSS v3 base score is 5.9 out of 10.
Is CVE-2023-6237 known to be exploited?
5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.