CVE-2026-89135

Certificate validation bypass via retained unverified CA

Published Sep 27, 2026 · Updated Sep 27, 2026

Certificate validation bypass in wolfSSL 5.8.4 through 5.9.2 allows attackers to establish trust in an unverified CA. After X509_verify_cert fails, it leaves the attacker-controlled CA in the shared CertManager, where type-blind sibling consumers treat it as trusted. Exposure requires OPENSSL_EXTRA with certificates enabled, a non-wolfCrypt-only build, and an application call to X509_verify_cert; affected consumers can then accept certificates anchored by that CA.

CVSS severityUnavailable
Unscored
EPSS probability0.15%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Certificate validation bypass in wolfSSL 5.8.4 through 5.9.2 allows attackers to establish trust in an unverified CA. After X509_verify_cert fails, it leaves the attacker-controlled CA in the shared CertManager, where type-blind sibling consumers treat it as trusted. Exposure requires OPENSSL_EXTRA with certificates enabled, a non-wolfCrypt-only build, and an application call to X509_verify_cert; affected consumers can then accept certificates anchored by that CA.

The record

CVE
CVE-2026-89135
Published
Sep 27, 2026
Updated
Sep 27, 2026
Vendor
wolfSSL
Product
wolfSSL
Classifications
T1553.004
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 27, 2026Record 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=5.8.4 <=5.9.2

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

wolfSSL · wolfSSLversion=5.8.4 <=5.9.2

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1553.004Install Root Certificate

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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