What is CVE-2026-26717?

CVE-2026-26717 is a medium-severity vulnerability in N/a, classified under CWE-208. CVSS score: 4.8/10. Published 2026-02-25.

How severe is CVE-2026-26717?

Medium severity. CVSS v3 base score is 4.8 out of 10.

Is CVE-2026-26717 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in N/a

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

Published 2026-02-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.005 (41.1th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 41.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001

Weakness classification (CWE)

CWE-208

Public proof-of-concept exploits

Rickidevs/CVE-2026-26717

References

Frequently asked questions

What is CVE-2026-26717?: CVE-2026-26717 is a medium-severity vulnerability in N/a, classified under CWE-208. CVSS score: 4.8/10. Published 2026-02-25.
How severe is CVE-2026-26717?: Medium severity. CVSS v3 base score is 4.8 out of 10.
Is CVE-2026-26717 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.