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CVE-2026-53636

Open edX LTI OAuth Replay Attack

4.7 Medium

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
Low
Integrity
Low
Availability
None

Exploit likelihood

0.28%Up 0.3 points since Jun 12, 2026
90%50%10%1%

What each source reports

CVE List Score used 4.7

Open edX LTI OAuth Replay Attack

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.

Record
CVE-2026-53636
CVSS 3.1
4.7 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness
CWE-294
Updated
2026-11-02
EUVDEUVD-2026-70222 4.7

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.

Record
EUVD-2026-70222
CVSS 3.1
4.7 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
Updated
2026-11-02
NVD 4.7

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.

Record
CVE-2026-53636
CVSS 3.1
4.7 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness
CWE-294
Updated
2026-11-02
OSV 4.7

Open edX LTI OAuth Replay Attack

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.

Record
CVE-2026-53636
CVSS 3.1
4.7 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness
CWE-294
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
first indexedCVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-53636 is a medium vulnerability (CVSS 4.7) in Openedx Openedx-platform, published September 2, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.28%, the 20th percentile. No source names a fixed version.

References

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