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OpenAdvisories
Medium · 4.7 CVE-2026-53636 EUVD-2026-70222

Open edX LTI OAuth Replay Attack

Published Sep 2, 2026 · Updated Sep 2, 2026 · Assigned by GitHub_M

Description

Open edX Platform enables the authoring and delivery of online learning at any scale. Prior to commit 3a5ac85, a security vulnerability has been identified in the Open edX LMS platform's LTI (Learning Tools Interoperability) Provider implementation. The validate_timestamp_and_nonce function in lms/djangoapps/lti_provider/signature_validator.py does not validate OAuth nonces or timestamps, allowing an attacker who captures a valid LTI launch request to replay it an unlimited number of times without detection. This issue has been patched via commit 3a5ac85.

Affected products

VendorProductAffectedFixed
openedx openedx-platform < 3a5ac856c79557c5c74d8b3e6578f289d7cceecd —

References