{"cve":"CVE-2023-3817","nvd":{"published":"2023-07-31T16:15:10.497","modified":"2026-10-14T22:17:16.080","status":"Modified","description":"Issue summary: Checking excessively long DH keys or parameters may be very slow.\n\nImpact summary: Applications that use the functions DH_check(), DH_check_ex()\nor EVP_PKEY_param_check() to check a DH key or DH parameters may experience long\ndelays. Where the key or parameters that are being checked have been obtained\nfrom an untrusted source this may lead to a Denial of Service.\n\nThe function DH_check() performs various checks on DH parameters. After fixing\nCVE-2023-3446 it was discovered that a large q parameter value can also trigger\nan overly long computation during some of these checks. A correct q value,\nif present, cannot be larger than the modulus p parameter, thus it is\nunnecessary to perform these checks if q is larger than p.\n\nAn application that calls DH_check() and supplies a key or parameters obtained\nfrom an untrusted source could be vulnerable to a Denial of Service attack.\n\nThe function DH_check() is itself called by a number of other OpenSSL functions.\nAn application calling any of those other functions may similarly be affected.\nThe other functions affected by this are DH_check_ex() and\nEVP_PKEY_param_check().\n\nAlso vulnerable are the OpenSSL dhparam and pkeyparam command line applications\nwhen using the \"-check\" option.\n\nThe OpenSSL SSL/TLS implementation is not affected by this issue.\n\nThe OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3},"cwes":["CWE-834","CWE-606"],"references":["https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=6a1eb62c29db6cb5eec707f9338aee00f44e26f5","https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=869ad69aadd985c7b8ca6f4e5dd0eb274c9f3644","https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=9002fd07327a91f35ba6c1307e71fa6fd4409b7f","https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=91ddeba0f2269b017dc06c46c993a788974b1aa5","https://www.openssl.org/news/secadv/20230731.txt"],"products":["openssl:openssl"],"source":"nvd","synced_at":"2026-10-19T21:38:35.729974749+00:00"},"epss":{"cve":"CVE-2023-3817","score":0.03047,"percentile":0.87445,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}