CVE-2026-35188
Double-free When Checking OCSP Stapled Response
Description
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.
INFO
Published Date :
June 9, 2026, 5:17 p.m.
Last Modified :
June 15, 2026, 6:12 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update TLS client software to the latest version.
- Disable OCSP stapling if updates are unavailable.
- Avoid connecting to untrusted TLS servers.
Public PoC/Exploit Available at Github
CVE-2026-35188 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-2026-35188.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-35188 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-2026-35188
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-2026-35188 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-35188 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/131145d25659e8749a9ed1afb383484854cffb78 Types: Patch Added Reference Type OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/78d0154cffda03aaaac63a087cc523a6b35fa8fd Types: Patch Added Reference Type OpenSSL Software Foundation: https://openssl-library.org/news/secadv/20260609.txt Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 10, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L -
CVE Modified by [email protected]
Jun. 10, 2026
Action Type Old Value New Value Added Reference https://github.com/openssl/openssl/commit/131145d25659e8749a9ed1afb383484854cffb78 Added Reference https://github.com/openssl/openssl/commit/78d0154cffda03aaaac63a087cc523a6b35fa8fd Removed Reference https://github.com/openssl/security/commit/131145d25659e8749a9ed1afb383484854cffb78 Removed Reference https://github.com/openssl/security/commit/78d0154cffda03aaaac63a087cc523a6b35fa8fd -
New CVE Received by [email protected]
Jun. 09, 2026
Action Type Old Value New Value Added Description 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. Added CWE CWE-415 Added Reference https://github.com/openssl/security/commit/131145d25659e8749a9ed1afb383484854cffb78 Added Reference https://github.com/openssl/security/commit/78d0154cffda03aaaac63a087cc523a6b35fa8fd Added Reference https://openssl-library.org/news/secadv/20260609.txt