CVE-2026-53636

MEDIUM 4.7

Open edX LTI OAuth Replay Attack

CVSS Score

4.7

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-294
Vendor	openedx
Product	openedx-platform
Published	Sep 2, 2026
Last Updated	Sep 2, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Affected Versions

openedx / openedx-platform

< 3a5ac856c79557c5c74d8b3e6578f289d7cceecd

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/openedx/openedx-platform/security/advisories/GHSA-6gm5-c49g-p3h9 github.com: https://github.com/openedx/openedx-platform/commit/0a92cf25de8844bf840ffd5d18dcfd940031a2ba github.com: https://github.com/openedx/openedx-platform/commit/3a5ac856c79557c5c74d8b3e6578f289d7cceecd github.com: https://github.com/openedx/openedx-platform/commit/50af17b05d82a8c7e8e690cc2783a8a0ba330bc3