Description
In wolfSSL versions 5.7.2 through 5.9.2 there is a client-side implementation flaw in RFC 6961, multiple OCSP response stapling, which can lead to certificate forgery. When a wolfSSL client enables OCSP stapling with the HAVE_CERTIFICATE_STATUS_REQUEST_V2 feature and calls wolfSSL_UseOCSPStaplingV2(ssl, WOLFSSL_CSR2_OCSP_MULTI, options), the client accepts any certificate in the peer's chain as a certificate authority without verifying that the certificate is actually authorized to act as one. This means that an attacker who possesses any certificate that chains to a CA trusted by the client (along with its private key) can forge certificates for arbitrary identities that will be accepted as valid by the client. The end entity certificate of the server is stored in the persistent trust store, affecting subsequent connections that reuse the context even when OCSP multi usage is not employed. Found by internal wolfSSL testing.
Published: 2026-09-27
Score: 8.3 High
EPSS: < 1% Very Low
KEV: No
Impact: Certificate Forgery
Action: Patch Immediately
AI Analysis

Impact

The flaw in the wolfSSL library allows a client to accept any certificate in the presented chain as a trusted issuer, bypassing normal CA validation. When OCSP stapling v2 is enabled, an attacker who possesses a certificate that chains to a CA trusted by the client—and its private key—can create forged certificates for arbitrary identities. These forged certificates are then considered valid by the client, enabling impersonation or man‑in‑the‑middle attacks. The vulnerability stems from improper certificate chain verification and is identified as CWE‑295.

Affected Systems

wolfSSL library, versions 5.7.2 through 5.9.2, used when a client enables the HAVE_CERTIFICATE_STATUS_REQUEST_V2 feature and calls wolfSSL_UseOCSPStaplingV2 with the WOLFSSL_CSR2_OCSP_MULTI option.

Risk and Exploitability

The CVSS score of 8.3 designates high severity. The EPSS score is not available, indicating no data on current exploitation likelihood, though the vulnerability is not listed in the CISA KEV catalog. Attackers must target a wolfSSL‑based client that has OCSP stapling v2 enabled; a compromised certificate issuer can then sign forged server certificates that the client will accept. The exploit is client‑side, requiring the attacker to control a TLS client application or supply a trusted certificate chain. While no public exploits have been observed, the high impact warrants timely mitigation.

Generated by OpenCVE AI on September 27, 2026 at 10:21 UTC.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Upgrade the wolfSSL library to a version newer than 5.9.2, such as 5.9.3 or later, where the issue is fixed.
  • Disable the HAVE_CERTIFICATE_STATUS_REQUEST_V2 feature or refrain from calling wolfSSL_UseOCSPStaplingV2 until the library has been patched.
  • Verify that the client’s application does not rely on unverified chain certificates and configures strict validation of issuer certificates.

Generated by OpenCVE AI on September 27, 2026 at 10:21 UTC.

Tracking

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Advisories

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History

Wed, 30 Sep 2026 17:45:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'}


Tue, 29 Sep 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sun, 27 Sep 2026 10:45:00 +0000

Type Values Removed Values Added
First Time appeared Wolfssl
Wolfssl wolfssl
Vendors & Products Wolfssl
Wolfssl wolfssl

Sun, 27 Sep 2026 09:45:00 +0000

Type Values Removed Values Added
Description In wolfSSL versions 5.7.2 through 5.9.2 there is a client-side implementation flaw in RFC 6961, multiple OCSP response stapling, which can lead to certificate forgery. When a wolfSSL client enables OCSP stapling with the HAVE_CERTIFICATE_STATUS_REQUEST_V2 feature and calls wolfSSL_UseOCSPStaplingV2(ssl, WOLFSSL_CSR2_OCSP_MULTI, options), the client accepts any certificate in the peer's chain as a certificate authority without verifying that the certificate is actually authorized to act as one. This means that an attacker who possesses any certificate that chains to a CA trusted by the client (along with its private key) can forge certificates for arbitrary identities that will be accepted as valid by the client. The end entity certificate of the server is stored in the persistent trust store, affecting subsequent connections that reuse the context even when OCSP multi usage is not employed. Found by internal wolfSSL testing.
Title OCSP stapling v2 multi accepts non-CA chain certificates as issuers
Weaknesses CWE-295
References
Metrics cvssV4_0

{'score': 8.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: wolfSSL

Published:

Updated: 2026-09-29T16:04:31.679Z

Reserved: 2026-09-10T22:21:02.636Z

Link: CVE-2026-89102

cve-icon Vulnrichment

Updated: 2026-09-29T16:04:21.400Z

cve-icon NVD

Status : Analyzed

Published: 2026-09-27T10:16:58.767

Modified: 2026-09-30T17:30:04.583

Link: CVE-2026-89102

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-27T10:30:10Z

Weaknesses
  • CWE-295

    Improper Certificate Validation