SB2026100555 - Multiple vulnerabilities in wolfSSL
Published: October 5, 2026
Breakdown by Severity
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- Medium
- High
- Critical
Description
This security bulletin contains information about 11 vulnerabilities.
1) Improper Certificate Validation (CVE-ID: CVE-2026-93302)
CWE-ID: CWE-295 - Improper Certificate Validation
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to bypass peer authentication.
The vulnerability exists due to improper certificate validation in the trusted peer certificate verification path when processing a peer certificate. A remote attacker can present a forged certificate that reuses trusted certificate identity fields to bypass peer authentication.
Exploitation requires knowledge of the CA certificates loaded as trusted peer certificates.
2) Improper Certificate Validation (CVE-ID: CVE-2026-89102)
CWE-ID: CWE-295 - Improper Certificate Validation
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to forge certificates for arbitrary identities.
The vulnerability exists due to improper certificate validation in RFC 6961 multiple OCSP response stapling when processing a peer certificate chain. A remote attacker can present a certificate chain containing an unauthorized certificate authority to forge certificates for arbitrary identities.
Exploitation requires a certificate and private key that chain to a CA trusted by the client, and the affected client configuration uses OCSP multi stapling.
3) Improper Certificate Validation (CVE-ID: CVE-2026-89136)
CWE-ID: CWE-295 - Improper Certificate Validation
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to bypass server authentication.
The vulnerability exists due to improper certificate validation in raw public key handling when processing an unsolicited server_cert_type=RawPublicKey. A remote attacker can send an unsolicited raw public key certificate type to bypass server authentication.
Only builds with raw public key support enabled are affected.
4) Improper Authentication (CVE-ID: CVE-2026-93304)
CWE-ID: CWE-287 - Improper Authentication
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to impersonate a server.
The vulnerability exists due to improper state management in the TLS 1.2 and DTLS 1.2 handshake when receiving an out-of-order ChangeCipherSpec message before ClientKeyExchange. A remote attacker can send an out-of-order ChangeCipherSpec message to impersonate a server.
Certificate-suite exploitation requires a man-in-the-middle position, while PSK connections can be attacked by a fake server without knowledge of the PSK.
5) Improper Certificate Validation (CVE-ID: CVE-2026-89133)
CWE-ID: CWE-295 - Improper Certificate Validation
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to use certificates for unauthorized hostnames.
The vulnerability exists due to improper certificate validation in X.509 NameConstraints processing when validating a certificate chain with an unconstrained intermediate CA. A remote attacker can present a certificate chain for an unauthorized hostname to use certificates for unauthorized hostnames.
The issue affects certificate validation where name constraint extensions are used.
6) Improper Certificate Validation (CVE-ID: CVE-2026-89134)
CWE-ID: CWE-295 - Improper Certificate Validation
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to use certificates for unauthorized hostnames.
The vulnerability exists due to improper certificate validation in the subject CN dNSName name-constraint check when processing a certificate with a non-dNSName subject alternative name. A remote attacker can present a certificate with an out-of-scope common name to use certificates for unauthorized hostnames.
The certificate must lack a dNSName SAN while containing another SAN type.
7) Improper Certificate Validation (CVE-ID: CVE-2026-89135)
CWE-ID: CWE-295 - Improper Certificate Validation
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to bypass certificate validation in sibling consumers.
The vulnerability exists due to improper certificate validation in X509_verify_cert when a certificate verification attempt fails. A remote attacker can cause a failed certificate verification that adds an unverified CA to the shared certificate manager to bypass certificate validation in sibling consumers.
The issue requires an application using X509_verify_cert in an OPENSSL_EXTRA build.
8) Use-after-free (CVE-ID: CVE-2026-15442)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a heap-use-after-free.
The vulnerability exists due to a heap-use-after-free in the TLS shutdown state handling when an application reads data after a partial wolfSSL_read() and bidirectional wolfSSL_shutdown(). A remote attacker can continue sending data during shutdown to cause a heap-use-after-free.
The condition requires a partial read, which can occur when the application uses a small user buffer.
9) Improper Certificate Validation (CVE-ID: CVE-2026-94417)
CWE-ID: CWE-295 - Improper Certificate Validation
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to bypass certificate revocation checking.
The vulnerability exists due to improper certificate validation in ProcessPeerCerts() when processing a peer certificate without an Authority Information Access OCSP URL. A remote attacker can present a revoked certificate without an OCSP responder URL to bypass certificate revocation checking.
The issue requires OCSP and CRL checking to be enabled on the same certificate manager or context with a CRL loaded.
10) Improper Certificate Validation (CVE-ID: CVE-2026-94418)
CWE-ID: CWE-295 - Improper Certificate Validation
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to bypass certificate signature validation.
The vulnerability exists due to improper certificate validation in ProcessPeerCertParse() when merging certificate signature and parsing results. A remote attacker can present a self-made certificate with an invalid signature and an expired validity period to bypass certificate signature validation.
The issue requires WOLFSSL_SMALL_CERT_VERIFY and a peer-verification callback that overrides certificate date errors.
11) Authentication Bypass by Primary Weakness (CVE-ID: CVE-2026-94419)
CWE-ID: CWE-305 - Authentication Bypass by Primary Weakness
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to impersonate a previously authenticated server.
The vulnerability exists due to improper session management in the process-global SessionCache when handling legacy client session references. A remote attacker can cause a session cache entry to be overwritten through a matching TLS session ID to impersonate a previously authenticated server.
The issue requires the legacy wolfSSL_get_session() or SSL_get_session() flow followed by wolfSSL_set_session() and affects TLS 1.2 and earlier or DTLS 1.2 and earlier.
Remediation
Install update from vendor's website.