Auth bypass in Cern Indico
CVE-2025-53640
Indico is an event management system that uses Flask-Multipass, a multi-backend authentication system for Flask. Starting in version 2.2 and prior to version 3.3.7, an endpoint used to display details of users listed in certain fields (such as ACLs) could be misused to dump basic user details (such as name, affiliation and email) in bulk. Version 3.3.7 fixes the issue. Owners of instances that allow everyone to create a user account, who wish to truly restrict access to these user details, should consider restricting user search to managers. As a workaround, it is possible to restrict access to the affected endpoints (e.g. in the webserver config), but doing so would break certain form fields which could no longer show the details of the users listed in those fields, so upgrading instead is highly recommended.
Vulnerability class: Information Disclosure
EPSS: 0.006 (43.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Cern Indico
- Indico — versions >= 2.2, < 3.3.7
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Product, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
- af854a3a-2127-422b-91ae-364da2661108 (Exploit, Third Party Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Exploit, Mitigation, Third Party Advisory)
Frequently asked questions
- What is CVE-2025-53640?
- CVE-2025-53640 is a medium-severity vulnerability in Cern Indico, classified under Information Disclosure. CVSS score: 6.5/10. Published 2025-07-14.
- How severe is CVE-2025-53640?
- Medium severity. CVSS v3 base score is 6.5 out of 10.
- Is CVE-2025-53640 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.