Vulnerability · Published Oct 5, 2026 · Assigned by Fluid Attacks
CVE-2026-91107openSIS Classic 9.3 - Insecure Direct Object Reference (IDOR)
Critical 9.3
In plain English
A critical-severity authorization bypass via user-controlled key in openSIS-Classic from OS4ED. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities).
Severity (CVSS 4.0)9.3Critical
Exploit odds (30 days)0.2%top 85.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
openSIS Classic 9.3 allows an authenticated user with the built-in teacher role can select an arbitrary staff record through staff_id and cause the School Information update path to reset that selected account's password.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| OS4ED | openSIS-Classic | 9.3 |
Weakness: CWE-639 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N