CVE-2025-4575

Certificate trust-policy bypass via misfiled rejected use

Published May 22, 2025 · Updated May 22, 2025

Improper certificate validation in OpenSSL 3.5.0 allows local users to mark a rejected certificate purpose as trusted via x509 -addreject. In apps/x509.c, x509_main pushes the option's ASN.1 purpose object onto the trust stack instead of the reject stack. Only trusted-certificate-format users who invoke the command to add rejected uses are exposed, and the resulting certificate can be accepted for a purpose intended to be denied.

CVSS severity6.5
Medium
EPSS probability0.36%
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 3.5.0 allows local users to mark a rejected certificate purpose as trusted via x509 -addreject. In apps/x509.c, x509_main pushes the option's ASN.1 purpose object onto the trust stack instead of the reject stack. Only trusted-certificate-format users who invoke the command to add rejected uses are exposed, and the resulting certificate can be accepted for a purpose intended to be denied.

The record

CVE
CVE-2025-4575
Published
May 22, 2025
Updated
May 22, 2025
Vendor
OpenSSL Project
Product
OpenSSL
Classifications
CWE-295
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. May 22, 2025CVE publishedPublication date reported by the CVE source.
  2. May 22, 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=3.5.0 <3.5.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

OpenSSL Project · OpenSSLversion=3.5.0 <3.5.1

Published CVSS scores

6.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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.

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No observations available

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

Weakness, pattern, technique

CWE-295Improper Certificate Validation

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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