---
id: CVE-2023-6237
title: |-
  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
summary: |-
  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…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-606
published: '2024-04-25'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T23:17:19.220'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2023-6237'
references:
  - url: >-
      https://github.com/openssl/openssl/commit/0b0f7abfb37350794a4b8960fafc292cd5d1b84d
    label: openssl-security@openssl.org
  - url: >-
      https://github.com/openssl/openssl/commit/18c02492138d1eb8b6548cb26e7b625fb2414a2a
    label: openssl-security@openssl.org
  - url: >-
      https://github.com/openssl/openssl/commit/a830f551557d3d66a84bbb18a5b889c640c36294
    label: openssl-security@openssl.org
  - url: 'https://www.openssl.org/news/secadv/20240115.txt'
    label: openssl-security@openssl.org
  - url: 'http://www.openwall.com/lists/oss-security/2024/03/11/1'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://github.com/openssl/openssl/commit/0b0f7abfb37350794a4b8960fafc292cd5d1b84d
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://github.com/openssl/openssl/commit/18c02492138d1eb8b6548cb26e7b625fb2414a2a
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://github.com/openssl/openssl/commit/a830f551557d3d66a84bbb18a5b889c640c36294
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.netapp.com/advisory/ntap-20240531-0007/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.openssl.org/news/secadv/20240115.txt'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-265688.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-331112.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-769027.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-915275.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.02303
epssPercentile: 0.82983
ingestedAt: '2026-10-15T00:02:07.137Z'
vendor: OpenSSL
product: OpenSSL
affected:
  - OpenSSL >= 3.0.0 < 3.0.13
  - OpenSSL >= 3.1.0 < 3.1.5
  - OpenSSL >= 3.2.0 < 3.2.1
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2024-08-20T14:44:52.382969Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.