CVE-2016-5431 is a high-severity (CVSS 7.5) Broken Cryptographic Algorithm vulnerability in gree/jose. A fix is available for gree/jose — see the affected versions and patch details below.
PHP JOSE Library by Gree Inc. Uses a Broken or Risky Cryptographic Algorithm
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
gree/joseReal-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
The PHP JOSE Library by Gree Inc. before version 2.2.1 is vulnerable to key confusion/algorithm substitution in the JWS component resulting in bypassing the signature verification via crafted tokens.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | gree/jose | all versions | 2.2.1composer require gree/jose:^2.2.1 |
Affected Products
php josephp_jose_projectDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for gree/jose, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update gree/jose to 2.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-5431 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 CVE-2016-5431 in your dependencies?
Find it across Packagist, including transitive dependencies.