{"id":"CVE-2026-53636","aliases":["EUVD-2026-70222","GHSA-6gm5-c49g-p3h9"],"status":"published","title":"Open edX LTI OAuth Replay Attack","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.","severity":{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0028,"percentile":0.20676,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-294"],"published":"2026-09-02T16:54:10Z","modified":"2026-10-28T02:30:41Z","products":[{"vendor":"openedx","product":"openedx-platform"}],"references":[{"url":"https://github.com/openedx/openedx-platform/security/advisories/GHSA-6gm5-c49g-p3h9","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/openedx/openedx-platform/commit/0a92cf25de8844bf840ffd5d18dcfd940031a2ba","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/openedx/openedx-platform/commit/3a5ac856c79557c5c74d8b3e6578f289d7cceecd","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/openedx/openedx-platform/commit/50af17b05d82a8c7e8e690cc2783a8a0ba330bc3","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53636.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53636","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-53636","title":"Open edX LTI OAuth Replay Attack","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.","status":"published","published":"2026-09-02T16:54:10.403Z","modified":"2026-09-02T18:03:41.926Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T14:20:00.11477Z"}],"euvd":[{"id":"EUVD-2026-70222","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.","status":"published","published":"2026-09-02T16:54:10Z","modified":"2026-09-02T18:03:41Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T18:01:14.689075Z"}],"nvd":[{"id":"CVE-2026-53636","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.","status":"published","published":"2026-09-02T17:17:45.917Z","modified":"2026-09-09T21:04:42.813Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T14:12:43.399612Z"}],"osv":[{"id":"CVE-2026-53636","title":"Open edX LTI OAuth Replay Attack","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.","status":"published","published":"2026-09-02T16:54:10.403Z","modified":"2026-10-28T02:30:41.014844722Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-294"],"updated_at":"2026-11-02T15:45:08.132336Z"}]}}