CVE-2023-37897: 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 vul...

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.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

2.26%

80.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Getgrav	Grav	1.7.42
Getgrav	Grav	1.7.42.1

References

https://github.com/getgrav/grav/commit/71bbed12f950de8335006d7f91112263d8504f1bProduct
https://github.com/getgrav/grav/commit/b4c62101a43051fc7f5349c7d0a5b6085375c1d7Patch
https://github.com/getgrav/grav/security/advisories/GHSA-9436-3gmp-4f53Exploit, Mitigation, Vendor Advisory
https://github.com/getgrav/grav/commit/71bbed12f950de8335006d7f91112263d8504f1bProduct
https://github.com/getgrav/grav/commit/b4c62101a43051fc7f5349c7d0a5b6085375c1d7Patch
https://github.com/getgrav/grav/security/advisories/GHSA-9436-3gmp-4f53Exploit, Mitigation, Vendor Advisory

Timeline

Published: Jul 18, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-37897?

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.

How severe is CVE-2023-37897?

CVE-2023-37897 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 2.26% probability of exploitation in the next 30 days.

How do I fix CVE-2023-37897?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.