CVE-2026-35188
Published:June 09, 2026
Updated:August 06, 2026
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.
Affected Packages
openssl (CONDA):
Affected version(s) >=3.6.0 <3.6.3Fix Suggestion:
Update to version 3.6.3https://github.com/openssl/openssl.git (GITHUB):
Affected version(s) =openssl-4.0.0 <openssl-4.0.1Fix Suggestion:
Update to version openssl-4.0.1https://github.com/openssl/openssl.git (GITHUB):
Affected version(s) >=openssl-3.6.0 <openssl-3.6.3Fix Suggestion:
Update to version openssl-3.6.3Related Resources (7)
Do you need more information?
Contact UsCVSS v4
Base Score:
2.3
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
LOW
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
5
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
LOW
Weakness Type (CWE)
Double Free
EPSS
Base Score:
0.30