CVE-2026-39957: Lychee has Broken Access Control in SharingController::listAll() leaks private album sharing metadata to unauthorized users

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-09 · updated 2026-10-26
Weakness: CWE-863

Description

Lychee is a free, open-source photo-management tool. Prior to 7.5.4, a SQL operator-precedence bug in SharingController::listAll() causes the orWhereNotNull('user_group_id') clause to escape the ownership filter applied by the when() block. Any authenticated non-admin user with upload permission who owns at least one album can retrieve all user-group-based sharing permissions across the entire instance, including private albums owned by other users. This vulnerability is fixed in 7.5.4.

Affected products

LycheeOrg Lychee: before 7.5.4 — fixed in 7.5.4

How to fix

Upgrade to a fixed version: LycheeOrg Lychee 7.5.4. Check the vendor advisory for mitigations.

References

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