CVE-2023-23611 is a medium-severity (CVSS 5.4) CWE-862 vulnerability in lti-consumer-xblock. A fix is available for lti-consumer-xblock — see the affected versions and patch details below.
xblock-lti-consumer contain Missing Authorization in Grade Pass Back Implementation
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-23611.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-23611 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
lti-consumer-xblockReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Problem
TL;DR: Any LTI tool that is integrated with on the Open edX platform can post a grade back for any LTI XBlock so long as it knows or can guess the block location for that XBlock.
In LTI 1.3, LTI tools can "pass back" scores that learners earn while using LTI tools to the edX platform. The edX platform then stores those LTI scores in a separate table. If the right conditions are met, these scores are then persisted to the LMS grades tables.
LTI tools can create what are called "line items" on the edX platform. A line item can be thought of as a column in a grade book; it stores results for a specific activity (i.e. XBlock) for a specific set of users (i.e. users in the course using the XBlock). A line item has an optional resource_link_id field, which is basically the XBlock location. An LTI tool can supply any value for this field.
An LTI tool submits scores to the edX platform for line items. The code that uploads that score to the LMS grade tables determines which XBlock to upload the grades for by reading the resource_link_id field of the associated line item. Because the LTI tool could have submitted any value for the resource_link_id field, this introduces the potential for a nefarious LTI tool to submit scores for any LTI XBlock on the platform.
Impact
Any LTI tool that is integrated with on the Open edX platform can post a grade back for any LTI XBlock so long as it knows the resource_link_id (i.e. block location) for that XBlock.
The impact is a loss of integrity for LTI XBlock grades.
Patches
No available patch
Workarounds
No
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | lti-consumer-xblock | ≥ 7.0.0&&< 7.2.2 | 7.2.2pip install --upgrade 'lti-consumer-xblock==7.2.2' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for lti-consumer-xblock, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update lti-consumer-xblock to 7.2.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-23611 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-23611 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-23611. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-23611 in your dependencies?
O3 Security finds CVE-2023-23611 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.