LTI 1.3 Tool Library's Nonce Claim Value not validated against nonce value sent in Authentication Request before v5.0GHSA-5p73-qg2v-383h
HIGHGHSA-5p73-qg2v-383h is a high-severity (CVSS 7.5) CWE-294 vulnerability in packbackbooks/lti-1-3-php-library. A fix is available for packbackbooks/lti-1-3-php-library — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- 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 GHSA-5p73-qg2v-383h.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
packbackbooks/lti-1-3-php-libraryReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
LTI 1.3 Tool Library is a library used for building IMS-certified LTI 1.3 tool providers in PHP. Prior to version 5.0, the Nonce Claim Value was not being validated against the nonce value sent in the Authentication Request. Users should upgrade to version 5.0 to receive a patch. There are currently no known workarounds.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | packbackbooks/lti-1-3-php-library | all versions | 5.0composer require packbackbooks/lti-1-3-php-library:^5.0 |
Affected Products
lti 1.3 tool librarypackbackDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for packbackbooks/lti-1-3-php-library, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update packbackbooks/lti-1-3-php-library to 5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5p73-qg2v-383h 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.
Frequently Asked Questions
Is GHSA-5p73-qg2v-383h in your dependencies?
Find it across Packagist, including transitive dependencies.