Open edX Platform LTI Provider signature_validator.py validate_timestamp_and_nonce authentication replay

CVSS Meta Temp Score
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CTI Interest Score
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5.9$0-$5k0.48+

Summaryinfo

A vulnerability classified as critical has been found in Open edX Platform. This affects the function validate_timestamp_and_nonce of the file lms/djangoapps/lti_provider/signature_validator.py of the component LTI Provider. This manipulation causes authentication replay. This vulnerability is tracked as CVE-2026-53636. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Open edX Platform (version now known). It has been declared as critical. Affected by this vulnerability is the function validate_timestamp_and_nonce of the file lms/djangoapps/lti_provider/signature_validator.py of the component LTI Provider. The manipulation with an unknown input leads to a authentication replay vulnerability. The CWE definition for the vulnerability is CWE-294. A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-53636 since 06/09/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1040 for this issue.

Applying the patch 3a5ac856c79557c5c74d8b3e6578f289d7cceecd is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

Name

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.0
VulDB Meta Temp Score: 5.9

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.7
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authentication replay
CWE: CWE-294 / CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: 3a5ac856c79557c5c74d8b3e6578f289d7cceecd

Timelineinfo

06/09/2026 CVE reserved
09/02/2026 +85 days Advisory disclosed
09/02/2026 +0 days VulDB entry created
09/02/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-53636 (🔒)
GCVE (CVE): GCVE-0-2026-53636
GCVE (VulDB): GCVE-100-398257

Entryinfo

Created: 09/02/2026 19:16
Changes: 09/02/2026 19:16 (65)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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