> CVE-2026-19445 [CRITICAL]

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PUBLISHED
2026-09-30 17:16
MODIFIED
2026-09-30 17:31
CVSS_SCORE V3
9.2
EPSS (Prob. Exploit)
0.43%
Top 63.9%
DATA SOURCES:
NVD đź”— 2026-09-30 CWE MITRE đź”— 2026-10-01 FIRST EPSS đź”— 2026-10-22 OSV đź”— 2026-10-19 MSRC đź”— 2026-10-04

> 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.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

> MÉTRIQUES CVSS DÉTAILLÉES

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
High (H)
Conditions spécifiques doivent être réunies pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
High (H)
Divulgation totale d'informations
I (Impact Intégrité)
Integrity Impact
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
Low (L)
Interruption partielle du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
Low
Interruption partielle du service possible

> WEAKNESSES

CWE-416

> CWE DETAILED DESCRIPTIONS

CWE-416: Use After Free - The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

> RED HAT SECURITY ADVISORIES

Red Hat Security Advisory: python3.12 security update
An update for python3.12 is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring Syste...
Red Hat Security Advisory: python3.12 security update
An update for python3.12 is now available for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring Syste...
Red Hat Security Advisory: python3.14 security update
An update for python3.14 is now available for Red Hat Enterprise Linux 10. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring Syst...
Red Hat Security Advisory: python3.14 security update
An update for python3.14 is now available for Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring Syste...
Red Hat Security Advisory: python3.12 security update
An update for python3.12 is now available for Red Hat Enterprise Linux 10. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring Syst...
Red Hat Security Advisory: Red Hat Update Infrastructure 5.3 security update
The latest release of Red Hat Update Infrastructure. For more details, see the product documentation.
Red Hat Security Advisory: python3 security update
An update for python3 is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (...
Red Hat Security Advisory: Red Hat Cost Management On-Premise container image update
Updated container image for Red Hat Cost Management On-Premise is now available.

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Use-after-free of a server-side SSLContext when sni_callback switches contexts

AFFECTED PACKAGES:
Unknown / Unknown
206 versions affected
ALIASES:
BIT-libpython-2026-19445, BIT-python-2026-19445, BIT-python-min-2026-19445, PSF-2026-43

> HISTORIQUE DES MODIFICATIONS

Première apparition
30/09/2026 17:16
Source: NVD
đź“Š ENRICHISSEMENT 01/10/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-416: Use After Free - The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original p...
Total des modifications: 1 Dernière mise à jour: 3 weeks ago

> REFERENCES

https://github.com/python/cpython/issues/156293
https://github.com/python/cpython/pull/158504
https://mail.python.org/archives/list/[email protected]/thread/QMQIUQ...
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