CVE-2026-26717

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

CVSS v3.1

4.8 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS v3.1

4.8 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS

0.38% chance of exploitation in the next 30 days, 31th percentile

Published

2026-02-25

Updated

2026-02-26

Proof-of-concept exploits (1)

• Rickidevs/CVE-2026-267170★ · 2026-02-24

References

• CVE Record
• NVD entry

Related

• CVE-2026-32913
• CVE-2026-34070
• CVE-2026-35570
• CVE-2026-2670
• CVE-2026-26718
• CVE-2026-2669