CVE-2023-37897
HIGHServer-side Template Injection (SSTI) in grav
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.
Blast Radius
getgrav/gravReal-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
Grav is a file-based Web-platform built in PHP. Grav is subject to a server side template injection (SSTI) vulnerability. The fix for another SSTI vulnerability using |map, |filter and |reduce twigs implemented in the commit 71bbed1 introduces bypass of the denylist due to incorrect return value from isDangerousFunction(), which allows to execute the payload prepending double backslash (\\). The isDangerousFunction() check in version 1.7.42 and onwards retuns false value instead of true when the \ symbol is found in the $name. This vulnerability can be exploited if the attacker has access to: 1. an Administrator account, or 2. a non-administrator, user account that has Admin panel access and Create/Update page permissions. A fix for this vulnerability has been introduced in commit b4c6210 and is included in release version 1.7.42.2. Users are advised to upgrade. There are no known workarounds for this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | getgrav/grav | all versions | 1.7.42.2 |
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 getgrav/grav. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update getgrav/grav to 1.7.42.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-37897 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 pinpoints whether CVE-2023-37897 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2023-37897. 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-2023-37897 in your dependencies?
O3 detects CVE-2023-37897 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.