Description

Issue summary: Checking excessively long DH keys or parameters may be very slow. Impact summary: Applications that use the functions DH_check(), DH_check_ex() or EVP_PKEY_param_check() to check a DH key or DH parameters may experience long delays. Where the key or parameters that are being checked have been obtained from an untrusted source this may lead to a Denial of Service. The function DH_check() performs various checks on DH parameters. After fixing CVE-2023-3446 it was discovered that a large q parameter value can also trigger an overly long computation during some of these checks. A correct q value, if present, cannot be larger than the modulus p parameter, thus it is unnecessary to perform these checks if q is larger than p. An application that calls DH_check() and supplies a key or parameters obtained from an untrusted source could be vulnerable to a Denial of Service attack. The function DH_check() is itself called by a number of other OpenSSL functions. An application calling any of those other functions may similarly be affected. The other functions affected by this are DH_check_ex() and EVP_PKEY_param_check(). Also vulnerable are the OpenSSL dhparam and pkeyparam command line applications when using the "-check" option. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue.

Severity MEDIUM

CVSS Score 5.3

CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CWE CWE-606

Public Exploit ✅ No

Source NVD

Published 2023-07-31

Updated 2026-06-08

Modified 2025-05-05

Fix URL https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=6a1eb62c29db6cb5eec707f9338aee00f44e26f5

Software	From version	Fixed in
openssl	—	—