EUVD Vulnerability Catalog

EUVD-2026-90077

Severity: CRITICAL Base Score: 9.2 CVSS Version: 4.0

Vulnerability Description

A remote, unauthenticated TLS client can make a server crash or call through a freed pointer if its sni_callback assigns a different context to SSLSocket.context (the documented way to select a certificate per server name) and nothing else keeps the original ssl.SSLContext alive. Typical cases are servers that create an SSLContext per connection or replace it while connections are open; servers that wrap their listening socket with it are not affected. Mitigation: keep a reference to every SSLContext that sets sni_callback for the lifetime of the server. TLS clients are not affected.

CVSS Vector Analysis

Below is the complete, human-readable breakdown of the CVSS metric string: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

▪ Attack Vector (AV): Network
▪ Attack Complexity (AC): High
▪ Attack Requirements (AT): Present
▪ Privileges Required (PR): None
▪ User Interaction (UI): None
▪ Vulnerability Confidentiality Impact (VC): High
▪ Vulnerability Integrity Impact (VI): High
▪ Vulnerability Availability Impact (VA): Low
▪ Subsequent Confidentiality Impact (SC): None
▪ Subsequent Integrity Impact (SI): None
▪ Subsequent Availability Impact (SA): None

Affected Vendors & Systems

Vendor Python Software Foundation

References & Advisory Links

Metadata Profile

Database Authority

European Union Agency for Cybersecurity (ENISA) EUVD

Assigner

PSF

EPSS Probability

0

Known Aliases
CVE-2026-19445 GHSA-7jvw-f348-84gq
Published On

2026-09-30

Last Updated

2026-10-01