Issue summary: When a partial-chain certificate verification is enabled
together with OCSP response checking for the whole chain, a NULL dereference
will happen if the verified chain does not have a self-signed trusted anchor,
crashing the process.
Impact summary: A NULL pointer dereference can trigger a crash which leads to a
Denial of Service for an application.
When performing OCSP response checking for certificates in the verification
chain, the code always tries to access the next certificate as the issuer.
There is a check for a self-signed certificate. However with the partial
chain verification enabled when the chain does not have a self-signed trusted
anchor, the issuer will be NULL for the last certificate in the chain. A NULL
pointer dereference then happens.
This issue affects only applications which enable both OCSP verification
of the certificate chain (X509_V_FLAG_OCSP_RESP_CHECK_ALL) and partial
chain verification (X509_V_FLAG_PARTIAL_CHAIN) in the certificate
verification. Both flags are disabled by default. For that reason, we have
assigned Low severity to the issue.
No FIPS modules are affected by this issue as the affected code is outside
the OpenSSL FIPS module boundary.
Metrics
Affected Vendors & Products
References
History
Tue, 09 Jun 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Issue summary: When a partial-chain certificate verification is enabled together with OCSP response checking for the whole chain, a NULL dereference will happen if the verified chain does not have a self-signed trusted anchor, crashing the process. Impact summary: A NULL pointer dereference can trigger a crash which leads to a Denial of Service for an application. When performing OCSP response checking for certificates in the verification chain, the code always tries to access the next certificate as the issuer. There is a check for a self-signed certificate. However with the partial chain verification enabled when the chain does not have a self-signed trusted anchor, the issuer will be NULL for the last certificate in the chain. A NULL pointer dereference then happens. This issue affects only applications which enable both OCSP verification of the certificate chain (X509_V_FLAG_OCSP_RESP_CHECK_ALL) and partial chain verification (X509_V_FLAG_PARTIAL_CHAIN) in the certificate verification. Both flags are disabled by default. For that reason, we have assigned Low severity to the issue. No FIPS modules are affected by this issue as the affected code is outside the OpenSSL FIPS module boundary. | |
| Title | NULL Dereference in Certificate Verification with OCSP Checking | |
| Weaknesses | CWE-476 | |
| References |
|
Status: PUBLISHED
Assigner: openssl
Published:
Updated: 2026-06-09T16:03:25.934Z
Reserved: 2026-04-29T09:22:27.968Z
Link: CVE-2026-42765
No data.
Status : Received
Published: 2026-06-09T17:17:07.843
Modified: 2026-06-09T17:17:07.843
Link: CVE-2026-42765
No data.
OpenCVE Enrichment
No data.