Medium severity · published Sep 2, 2026
CVE-2026-53636
Open edX LTI OAuth Replay Attack
4.7
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 20% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
openedx-platform · openedx
< 3a5ac856c79557c5c74d8b3e6578f289d7cceecd · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-53636
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-53636
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
github.com
https://github.com/openedx/openedx-platform/security/advisories/GHSA-6gm5-c49g-p3h9
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