Improper Certificate Validation in python-certifi - CVE-2026-117611
Published: November 6, 2026
Vulnerability identifier: #VU159843
CSH Severity: Medium
CVSS v4: 9.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-117611
CWE-ID: CWE-295
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an unauthenticated network attacker to intercept and modify TLS communications accepted by applications using python-certifi.
The vulnerability exists due to python-certifi trusting emSign root certificates whose intermediate certificates were revoked for key compromise when applications validate certificate chains against its root store. An unauthenticated network attacker can use a compromised intermediate certificate authority key to issue certificates and conduct man-in-the-middle attacks against these applications.
Affected software
python-certifi
How to mitigate CVE-2026-117611
Install security update from vendor's website.
python-certifi - update to 2026.10.18