---
cve: "CVE-2023-3817"
severity: "MEDIUM"
cvss: 5.3
epss: "3.1%"
vendor: "OpenSSL"
kev: false
exploited: false
published: "2023-07-31 16:15:10"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-09T02:26:01+02:00"
---

# CVE-2023-3817

> 5.3 MEDIUM

## Beschreibung

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.

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Gering | warn |

## Patch verfügbar (OSV)

- 245cb0291e0db99d9ccf3692fa76f440b2b054c2 (Commit)
- 17a2c5111864d8e016c5f2d29c40a3746b559e9d (Commit)

## Referenzen

- <https://www.openssl.org/news/secadv/20230731.txt>
- <https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=6a1eb62c29db6cb5eec707f9338aee00f44e26f5>
- <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://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=869ad69aadd985c7b8ca6f4e5dd0eb274c9f3644>
- <http://seclists.org/fulldisclosure/2023/Jul/43>
- <http://www.openwall.com/lists/oss-security/2023/07/31/1>
- <http://www.openwall.com/lists/oss-security/2023/09/22/11>
- <http://www.openwall.com/lists/oss-security/2023/09/22/9>
- <http://www.openwall.com/lists/oss-security/2023/11/06/2>
- <https://lists.debian.org/debian-lts-announce/2023/08/msg00019.html>
- <https://security.gentoo.org/glsa/202402-08>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2023-3817) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_