CVE-2026-115557
Published on October 24, 2026

Distrust compromised intermediate certificates in ssl module
Python has added a denylist for known compromised certificates to the "ssl" module to ensure user safety even without certificate revocation configured. Known compromised certificates will automatically be rejected regardless of the SSLContext policy configuration.

Vendor Advisory NVD

Vulnerability Analysis

CVE-2026-115557 can be exploited with network access. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
PASSIVE

Weakness Type

Improper Check for Certificate Revocation

The software does not check or incorrectly checks the revocation status of a certificate, which may cause it to use a certificate that has been compromised. An improper check for certificate revocation is a far more serious flaw than related certificate failures. This is because the use of any revoked certificate is almost certainly malicious. The most common reason for certificate revocation is compromise of the system in question, with the result that no legitimate servers will be using a revoked certificate, unless they are sorely out of sync.


Affected Versions

Python Software Foundation CPython: