How severe is CVE-2026-26717?

CVE-2026-26717 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-26717 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-26717?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-26717 have an EU (EUVD) identifier?

Yes. CVE-2026-26717 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8680.

When was CVE-2026-26717 published?

CVE-2026-26717 was published on 2026-02-25 and last updated on 2026-06-17.

CVE-2026-26717

CVE-2026-26717 is a medium-severity vulnerability with a CVSS 3.x base score of 4.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-208.

Key facts

Severity: Medium (CVSS 3.x base score 4.8)
EPSS exploit prediction: 0% (30th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-8680
Weakness: CWE-208
Published: 2026-02-25
Last modified: 2026-06-17

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

Frequently asked questions

What is 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
How severe is CVE-2026-26717?: CVE-2026-26717 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-26717 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-26717?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-26717 have an EU (EUVD) identifier?: Yes. CVE-2026-26717 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8680.
When was CVE-2026-26717 published?: CVE-2026-26717 was published on 2026-02-25 and last updated on 2026-06-17.

References

Other CWE-208 vulnerabilities

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