GHSA-5hm8-vh6r-2cjq is a medium-severity (CVSS 5.9) vulnerability in codeigniter4/shield. 1 public exploit reference exists, so weaponization risk is real. A fix is available for codeigniter4/shield — see the affected versions and patch details below.
CodeIgniter Shield Vulnerable to SameSite Attackers Bypassing the CSRF Protection
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-5hm8-vh6r-2cjq.
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
GHSA-5hm8-vh6r-2cjq 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 379,842 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
codeigniter4/shieldReal-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
Impact
This vulnerability may allow SameSite Attackers to bypass the CodeIgniter4 CSRF protection mechanism with CodeIgniter Shield.
For this attack to succeed, the attacker must have direct (or indirect, e.g., XSS) control over a subdomain site (e.g., https://a.example.com/) of the target site (e.g., http://example.com/).
This vulnerability exists whether Config\Security::$csrfProtection is 'cookie' or 'session'.
It is also exploitable whether Config\Security::$regenerate is true or false.
Patches
Upgrade to CodeIgniter v4.2.3 or later and Shield v1.0.0-beta.2 or later.
Workarounds
Do all of the following:
- set
Config\Security::$csrfProtectionto'session' - remove old session data right after login (immediately after ID and password match)
- regenerate CSRF token right after login (immediately after ID and password match)
References
For more information
If you have any questions or comments about this advisory:
- Open an issue or discussion in codeigniter4/shield
- Email us at [email protected]
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | codeigniter4/shield | ≥ 1.0.0-beta&&< 1.0.0-beta.2 | 1.0.0-beta.2composer require codeigniter4/shield:^1.0.0-beta.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for codeigniter4/shield, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update codeigniter4/shield to 1.0.0-beta.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5hm8-vh6r-2cjq is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-5hm8-vh6r-2cjq can be triaged on real exposure rather than presence alone.
Tailored to GHSA-5hm8-vh6r-2cjq. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-5hm8-vh6r-2cjq in your dependencies?
O3 Security finds GHSA-5hm8-vh6r-2cjq across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.