CVE-2023-30861
Vulnérabilité élevée dans flask (pallets)
Description
Flask is a lightweight WSGI web application framework. When all of the following conditions are met, a response containing data intended for one client may be cached and subsequently sent by the proxy to other clients. If the proxy also caches `Set-Cookie` headers, it may send one client's `session` cookie to other clients. The severity depends on the application's use of the session and the proxy's behavior regarding cookies. The risk depends on all these conditions being met. 1. The application must be hosted behind a caching proxy that does not strip cookies or ignore responses with cookies. 2. The application sets `session.permanent = True` 3. The application does not access or modify the session at any point during a request. 4. `SESSION_REFRESH_EACH_REQUEST` enabled (the default). 5. The application does not set a `Cache-Control` header to indicate that a page is private or should not be cached. This happens because vulnerable versions of Flask only set the `Vary: Cookie` header when the session is accessed or modified, not when it is refreshed (re-sent to update the expiration) without being accessed or modified. This issue has been fixed in versions 2.3.2 and 2.2.5.
Gravité et risque d'exploitation
CVE-2023-30861 obtient un score CVSS de 7.5/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 1.26 %, ce qui la place devant 69.2 % des CVE référencées.
Que faire ?
- Vérifiez si flask (versions >= 2.3.0, < 2.3.2, < 2.2.5) 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/pallets/flask/security/advisories/GHSA-m2qf-hxjv-5gpq
- https://github.com/pallets/flask/commit/70f906c51ce49c485f1d355703e9cc3386b1cc2b
- https://github.com/pallets/flask/commit/afd63b16170b7c047f5758eb910c416511e9c965
- https://github.com/pallets/flask/releases/tag/2.2.5
- https://github.com/pallets/flask/releases/tag/2.3.2
- https://www.debian.org/security/2023/dsa-5442
- https://security.netapp.com/advisory/ntap-20230818-0006/
- https://lists.debian.org/debian-lts-announce/2023/08/msg00024.html