> CVE-2026-19553 [HIGH]

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PUBLISHED
2026-09-30 17:16
MODIFIED
2026-09-30 17:31
CVSS_SCORE V3
7.6
EPSS (Prob. Exploit)
0.40%
Top 66.8%
DATA SOURCES:
NVD 🔗 2026-09-30 RED HAT 🔗 2026-10-04 CWE MITRE 🔗 2026-10-01 FIRST EPSS 🔗 2026-10-22 OSV 🔗 2026-10-19 MSRC 🔗 2026-10-04

> DESCRIPTION

ssl.SSLContext.wrap_bio() didn't require the server_hostname argument to not be None if ssl.SSLContext.check_hostname was set. Due to a missing parameter check in SSLObject, if the server_hostname argument isn't supplied then hostname verification would be silently skipped. This defect could lead to programs where certificate hostname verification *appeared* to be succeeding with SSLContext.check_hostname = True and no ValueError being raised due to misconfiguration. If the program passes a server_hostname value that isn't an empty string or None to any of these APIs then certificate hostname verification proceeds as expected and the program is not affected by this vulnerability. Mitigating this vulnerability doesn't require updating Python or applying the patch. To mitigate, pass a valid non-None and non-empty server_hostname value to SSLContext.wrap_bio(), asyncio.create_connection(), or asyncio.loop.start_tls() and certificate hostname verification will proceed as expected. Upgrading to the latest version of Python or applying the patch only changes the behavior from silently skipping hostname verification to raising a ValueError, similar to SSLContext.wrap_socket(), when server_hostname isn't supplied.

> AFFECTED_PRODUCTS

Red Hat - Red Hat Hardened Images
Version: 14
Red Hat - Red Hat Hardened Images
Version: 10
Red Hat - Red Hat Hardened Images
Version: 11
Red Hat - Red Hat Hardened Images
Version: 13
Red Hat - Red Hat Hardened Images
Version: 12

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/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:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/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
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
Unknown (P)
Interaction inconnue
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
None (N)
Aucune interruption de service

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
None
Aucune interruption de service

> WEAKNESSES

CWE-297

> CWE DETAILED DESCRIPTIONS

CWE-297: Improper Validation of Certificate with Host Mismatch - The product communicates with a host that provides a certificate, but the product does not properly ensure that the certificate is actually associated with that host.

> RED HAT SECURITY ADVISORIES

Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
An update for Red Hat Hardened Images RPMs is now available.
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
An update for Red Hat Hardened Images RPMs is now available.
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
An update for Red Hat Hardened Images RPMs is now available.
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
An update for Red Hat Hardened Images RPMs is now available.
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
An update for Red Hat Hardened Images RPMs is now available.
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.

> RED HAT SEVERITY ASSESSMENT

THREAT SEVERITY
Important

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

SSLContext.wrap_bio() missing validation of server_hostname parameter

AFFECTED PACKAGES:
Unknown / Unknown
206 versions affected
ALIASES:
BIT-libpython-2026-19553, BIT-python-2026-19553, BIT-python-min-2026-19553, PSF-2026-44

> HISTORIQUE DES MODIFICATIONS

Première apparition
30/09/2026 17:16
Source: NVD
📊 ENRICHISSEMENT 04/10/2026 05:01
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 23:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 22:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 21:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 20:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 19:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 18:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 17:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 16:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 15:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 14:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 13:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 12:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 11:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 10:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 09:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 08:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 07:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 06:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-297: Improper Validation of Certificate with Host Mismatch - The product communicates with a host that provides a certificate, but the product does not properly ensure that the certificate is actu...
📊 ENRICHISSEMENT 01/10/2026 05:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 04:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 03:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 02:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 01:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
{ "severity_scale": null, "threat_severity": "Important" }
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 00:30
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
N/A
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 01/10/2026 00:30
REDHAT
Champ modifié: Red Hat
Ancienne valeur:
Non
Nouvelle valeur:
Oui
Total des modifications: 27 Dernière mise à jour: 2 weeks ago

> REFERENCES

https://github.com/python/cpython/issues/156793
https://github.com/python/cpython/pull/158503
https://mail.python.org/archives/list/[email protected]/thread/QNZRG3...
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