OCSP stapling v2 multi accepts non-CA chain certificates as issuers
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- Spoofing
- Confidentiality · integrity · availability
- Low · High · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-295.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89102
- 2026-10-03 Alias added: GHSA-f972-pmrg-c63r
References
More Wolfssl vulnerabilities
- TI-2024-00830 SEGV and out of bounds memory read from malicious packet CVSS 3.1CRITICAL 9.1
- TI-2022-18557 In wolfSSL before 5.5.1, malicious clients can cause a buffer overflow during a TLS 1.3… CVSS 3.1HIGH 7.5
- TI-2025-10943 Potential DoS Vulnerability through Multiple KeyShareEntry with Same Group in TLS 1.3 ClientHello CVSS 4.0MEDIUM 6.3
- TI-2017-09737 wolfSSL Bleichenbacher/ROBOT CVSS 3.0HIGH 7.5
- TI-2019-08902 wolfSSL 4.0.0 has a Buffer Overflow in DoPreSharedKeys in tls13.c when a current identity… CVSS 3.1CRITICAL 9.8
- TI-2017-02021 Improper certificate validation in wolfSSL CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-89102 · CVE Program
- CVE-2026-89102 · NVD
- FIRST EPSS
- GHSA-f972-pmrg-c63r · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences