CVE-2026-15806

Description

The HTTPPasswordMgr class in the urllib.request module, along with its subclasses HTTPPasswordMgrWithDefaultRealm and HTTPPasswordMgrWithPriorAuth, did not take the URL scheme into account when matching stored credentials against a requested URL. Credentials added for an https:// URL were also used for requests to the same host over http://, so an attacker able to redirect or downgrade a client to plain HTTP (for example, via an HTTPS-to-HTTP redirect or an on-path position) could capture credentials in cleartext. Credentials added for http:// URLs could likewise be sent over https://. Credential matching is now scoped by URL scheme. Credentials registered with a URL that includes a scheme are only used for requests with the same scheme. Credentials registered with a bare authority (such as example.com or example.com:8080) continue to match any scheme, preserving compatibility with existing code, including proxy authentication. Users who cannot upgrade immediately can mitigate by ensuring that applications never make plain http:// requests to hosts for which credentials are registered, for example by not following redirects to http:// URLs.

Gravité et risque d'exploitation

CVE-2026-15806 obtient un score CVSS de 6.0/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.53 %, ce qui la place devant 43.5 % des CVE référencées.

Que faire ?

• Vérifiez si CPython (versions 3.14.0, 3.11.0, 3.13.0, <3.10.22, <3.15.0rc2, 3.15.0a1, 3.12.0, 0, <3.12.15, <3.14.8, <3.11.17, <3.13.16) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• https://github.com/python/cpython/issues/155694
• https://github.com/python/cpython/pull/155696
• https://mail.python.org/archives/list/security-announce@python.org/thread/3OKPE5S75KDNA7FY7AI3PL2MXM2X5RB3/
• https://github.com/python/cpython/commit/a0d023fbd23773e24b35d8368789470e22cda5d8
• https://github.com/python/cpython/commit/a2773a34183b7d94a243bb98fd658926cc5348ce
• https://github.com/python/cpython/commit/a7bb524fef61f77ede01f660ffbd591e1d5837ce
• https://github.com/python/cpython/commit/641be42bb07921ba0f8bffe228b1dc706b092ef6
• https://github.com/python/cpython/commit/851cf9a7142ecbdd39f831055533f58284ad2bcc
• https://github.com/python/cpython/commit/95355ee3a8e1d3c3d4858d1973aa42a9b91a2801
• https://github.com/python/cpython/commit/dac88d8615078c55f1304ea4c7a2d822700d4e5a