CVE-2026-26717
OpenFUN Richie LMS Timing Attack Vulnerability
Description
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
INFO
Published Date :
Feb. 25, 2026, 5:25 p.m.
Last Modified :
Feb. 25, 2026, 5:25 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-26717
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Implement constant-time comparison for HMAC verification.
- Replace non-constant time `==` with a secure alternative.
- Update OpenFUN Richie to a patched version if available.
Public PoC/Exploit Available at Github
CVE-2026-26717 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-26717.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-26717 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-26717
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
I discovered a Timing Attack vulnerability in the Richie LMS, developed by France Université Numérique (OpenFUN), and it was assigned the ID CVE-2026-26717 by MITRE.
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-26717 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-26717 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Feb. 25, 2026
Action Type Old Value New Value Added Description 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 Added Reference https://github.com/openfun/richie/commit/a1b5bbda3403d7debb466c303a32852925fcba5f Added Reference https://github.com/Rickidevs/CVE-2026-26717 Added Reference https://medium.com/@ordogh/cve-2026-26717-hmac-timing-attack-in-openfun-richie-lms-f04377efe83d?postPublishedType=repub