CVE-2026-42765

Name of the Vulnerable Software and Affected Versions OpenSSL (affected versions not specified)

Description A NULL pointer dereference occurs when partial-chain certificate verification is enabled alongside OCSP response checking for the entire chain, provided the verified chain lacks a self-signed trusted anchor. This happens because the code attempts to access the next certificate as the issuer, but the issuer remains NULL for the final certificate in the chain under these specific conditions. This can lead to a process crash and a subsequent Denial of Service. The issue specifically affects applications that enable both the X509 V FLAG OCSP RESP CHECK ALL and X509 V FLAG PARTIAL CHAIN flags, both of which are disabled by default.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability. Avoid enabling both X509 V FLAG OCSP RESP CHECK ALL and X509 V FLAG PARTIAL CHAIN flags simultaneously during certificate verification.