CVE-2023-0466Network attack vector

Certificate-policy bypass via disabled verification flag

Published Mar 28, 2023 · Updated Feb 19, 2025

Improper certificate validation in OpenSSL 1.0.2, 1.1.1, 3.0, and 3.1 allows attackers to bypass configured X.509 policies. X509_VERIFY_PARAM_add0_policy() adds a policy but fails to set X509_V_FLAG_POLICY_CHECK, so verification accepts certificates with invalid or incorrect policies. Reachability requires an application to rely on that function's documented implicit activation; policy checking is disabled by default and is not commonly used.

CVSS severity5.3
Medium
EPSS probability1.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate validation in OpenSSL 1.0.2, 1.1.1, 3.0, and 3.1 allows attackers to bypass configured X.509 policies. X509_VERIFY_PARAM_add0_policy() adds a policy but fails to set X509_V_FLAG_POLICY_CHECK, so verification accepts certificates with invalid or incorrect policies. Reachability requires an application to rely on that function's documented implicit activation; policy checking is disabled by default and is not commonly used.

The record

CVE
CVE-2023-0466
Published
Mar 28, 2023
Updated
Feb 19, 2025
Vendor
OpenSSL Project
Product
OpenSSL
Classifications
CWE-295, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 19, 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 <1.0.2zh
  2. Affected versionversion=1.1.1 <1.1.1u
  3. Affected versionversion=3.0.0 <3.0.9
  4. Affected versionversion=3.1.0 <3.1.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenSSL Project · OpenSSLversion=1.0.2 <1.0.2zh; version=1.1.1 <1.1.1u; version=3.0.0 <3.0.9; version=3.1.0 <3.1.1

Published CVSS scores

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

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-295Improper Certificate Validation
T1557Adversary-in-the-Middle

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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