CVE-2026-42765
NULL Dereference in Certificate Verification with OCSP Checking
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.
INFO
Published Date :
June 9, 2026, 5:17 p.m.
Last Modified :
June 15, 2026, 6:14 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Disable OCSP response checking for the whole chain.
- Disable partial chain verification.
- Update the affected application if patches are available.
Public PoC/Exploit Available at Github
CVE-2026-42765 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42765.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42765 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42765
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Aisle CVEs
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-42765 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-42765 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 15, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* versions from (including) 3.6.0 up to (excluding) 3.6.3 *cpe:2.3:a:openssl:openssl:4.0.0:-:*:*:*:*:*:* Added Reference Type OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/14340b7fa1d444615486bc137014b064e64ec334 Types: Patch Added Reference Type OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/eb345da18ce2216b2f3ade9c2bc23e068487fa97 Types: Patch Added Reference Type OpenSSL Software Foundation: https://openssl-library.org/news/secadv/20260609.txt Types: Vendor Advisory -
CVE Modified by [email protected]
Jun. 10, 2026
Action Type Old Value New Value Added Reference https://github.com/openssl/openssl/commit/14340b7fa1d444615486bc137014b064e64ec334 Added Reference https://github.com/openssl/openssl/commit/eb345da18ce2216b2f3ade9c2bc23e068487fa97 Removed Reference https://github.com/openssl/security/commit/14340b7fa1d444615486bc137014b064e64ec334 Removed Reference https://github.com/openssl/security/commit/eb345da18ce2216b2f3ade9c2bc23e068487fa97 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 09, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H -
New CVE Received by [email protected]
Jun. 09, 2026
Action Type Old Value New Value 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. Added CWE CWE-476 Added Reference https://github.com/openssl/security/commit/14340b7fa1d444615486bc137014b064e64ec334 Added Reference https://github.com/openssl/security/commit/eb345da18ce2216b2f3ade9c2bc23e068487fa97 Added Reference https://openssl-library.org/news/secadv/20260609.txt