Vulnerability · Published Oct 29, 2026 · Assigned by MON-CSIRT

CVE-2026-66091Unauthenticated IDOR Enables Disclosure of Other Users’ last-known details

Medium 6.9

In plain English

A medium-severity authorization bypass via user-controlled key in openEQUELLA from Apereo Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities).

Severity (CVSS 4.0)6.9Medium

Exploit odds (30 days)0.4%top 65.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

In openEQUELLA before 2026.1, the GET /api/userquery/userinfobackup endpoint performs no authentication or authorisation check. An unauthenticated attacker who supplies another user's uniqueId can retrieve that user's stored personal details (username, first name, last name and email address) within the same institution.

Affected products (as reported)

Vendor	Product	Versions
Apereo Foundation	openEQUELLA	2019.2 – before 2026.1

Weakness: CWE-639 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

References

https://github.com/openequella/openEQUELLA/security/advisories/GHSA-mxj9-pmpw-j4xw vendor-advisory
https://openequella.github.io/guides/ product