CVE-2026-26717
low-risk
Published 2026-02-25
An issue in OpenFUN Richie (LMS) in src/richie/apps/courses/api.py. The application used the non-constant time == operator for HMAC signature verification in the sync_course_run_from_request function. This allows remote attackers to forge valid signatures and bypass authentication by measuring response time discrepancies
Do I need to act?
-
0.10% chance of exploitation
EPSS score — low exploit probability
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
4
CVSS 4.8/10
Medium
NETWORK
/ HIGH complexity
20
/ 100
low-risk
Severity
15/34 · Moderate
Exploitability
0/34 · Minimal
Exposure
5/34 · Minimal