CVE intelligence

CVE-2026-35188

Vulnerability intelligence

Published Jun 9, 2026Sources checked Nov 12, 2026

5.0MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2026-35188 and is rated Medium severity with a CVSS score of 5.0. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Sep 7, 2026

See the Microsoft Security Update Guide for the update that applies to your product.

CISA KEVNot listedBased on the latest collected catalog

EPSS0.3%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-35188?

Issue summary: A malicious server can exploit TLS OCSP stapling by delivering a crafted response through the status_request extension, triggering a double-free in the client's certificate verification path.

Impact summary: Successful exploitation allows an attacker to corrupt heap memory via a double-free, potentially leading to a Denial of Service or possibly an attacker controlled code execution or other undefined behavior.

If OCSP stapling is enabled and the TLS client connects to a malicious server, a crafted OCSP stapled response can trigger a double free in the TLS client when the stapled response is checked.

The OCSP stapling is not enabled by default. Reliable code execution through a double-free is technically complex and highly environment-dependent but the Denial of Service impact is straightforward to achieve, warranting Moderate severity.

No FIPS modules are affected by this issue as the affected code is outside the OpenSSL FIPS module boundary.

Source: NVD