CVE-2023-3446Network attack vector

Excessive DH parameter checking causes denial of service

Published Jul 19, 2023 · Updated Apr 23, 2025

Denial of service in OpenSSL versions 1.0.2 through 3.1.1 allows remote attackers to consume excessive computation via oversized DH parameters. DH_check(), DH_check_ex(), and EVP_PKEY_param_check() continue expensive modulus checks after detecting an overlarge p value, and the dhparam and pkeyparam tools are exposed with -check. Exploitation requires an application or command-line invocation to process attacker-supplied parameters; TLS handling and FIPS providers are not affected.

CVSS severity5.3
Medium
EPSS probability6.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in OpenSSL versions 1.0.2 through 3.1.1 allows remote attackers to consume excessive computation via oversized DH parameters. DH_check(), DH_check_ex(), and EVP_PKEY_param_check() continue expensive modulus checks after detecting an overlarge p value, and the dhparam and pkeyparam tools are exposed with -check. Exploitation requires an application or command-line invocation to process attacker-supplied parameters; TLS handling and FIPS providers are not affected.

The record

CVE
CVE-2023-3446
Published
Jul 19, 2023
Updated
Apr 23, 2025
Vendor
OpenSSL Project
Product
OpenSSL
Classifications
CWE-606, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0.2 <1.0.2zi
  2. Affected versionversion=1.1.1 <1.1.1v
  3. Affected versionversion=3.0.0 <3.0.10
  4. Affected versionversion=3.1.0 <3.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenSSL Project · OpenSSLversion=1.0.2 <1.0.2zi; version=1.1.1 <1.1.1v; version=3.0.0 <3.0.10; version=3.1.0 <3.1.2

Published CVSS scores

5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-606Unchecked Input for Loop Condition
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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