GHSA-5G9F-CWWG-4P8G

Vulnerability from github – Published: 2026-06-26 22:10 – Updated: 2026-06-26 22:10
VLAI
Summary
PhpWeasyPrint vulnerable to arbitrary file deletion at shutdown via public $temporaryFiles
Details

Summary

AbstractGenerator::$temporaryFiles is a public array, and removeTemporaryFiles() — invoked from __destruct() and from a registered shutdown function — calls unlink() on every entry without verifying that the path is contained within the temporary folder. Any code holding a reference to a generator instance can push an arbitrary path into the array and have it deleted on script shutdown.

This mirrors the KnpLabs/snappy issue GHSA-87qc-37cw-84h4, patched in snappy 1.7.2.

Affected versions

pontedilana/php-weasyprint versions <= 2.5.1.

Patched in: 2.6.0.

Vulnerable code

src/AbstractGenerator.php:

public array $temporaryFiles = [];

// ...

public function removeTemporaryFiles(): void
{
    foreach ($this->temporaryFiles as $file) {
        $this->unlink($file);
    }
}

No path-containment check: whatever path is present in $temporaryFiles at shutdown is unlinked.

Proof of concept

<?php
use Pontedilana\PhpWeasyPrint\Pdf;

$pdf = new Pdf();
$pdf->temporaryFiles[] = '/var/www/html/.env';

// On shutdown, removeTemporaryFiles() deletes /var/www/html/.env.

Impact

  • Arbitrary file deletion bound to script shutdown, scoped to the privileges of the PHP process user.
  • Not directly exploitable on its own (the attacker already needs to influence the property in the same request). The risk is amplification: chained with a separate disclosure bug it enables leak-then-delete-to-cover-tracks, and any deserialization/property-oriented gadget that reaches this property becomes a generic file-delete primitive.

CWE-73 (External Control of File Name or Path).

Suggested fix

Only delete files that actually live inside the temporary folder, comparing canonical (realpath) paths:

public function removeTemporaryFiles(): void
{
    $temporaryFolderPath = \realpath($this->getTemporaryFolder());
    if (false === $temporaryFolderPath) {
        return;
    }
    $temporaryFolderPath = \rtrim($temporaryFolderPath, \DIRECTORY_SEPARATOR) . \DIRECTORY_SEPARATOR;

    foreach ($this->temporaryFiles as $file) {
        $filePath = \realpath($file);
        if (false === $filePath || 0 !== \strncmp($filePath, $temporaryFolderPath, \strlen($temporaryFolderPath))) {
            continue;
        }
        $this->unlink($file);
    }
}

(The trailing directory separator prevents a sibling folder such as /tmpevil from matching /tmp; strncmp is used instead of str_starts_with to keep PHP 7.4 compatibility.)

Credit

Reported upstream to KnpLabs/snappy (GHSA-87qc-37cw-84h4); identified as applicable to pontedilana/php-weasyprint, which mirrors the same code.

Severity
3.0 (Low)
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:L
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.5.1"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "pontedilana/php-weasyprint"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.6.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-49358"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-73"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-26T22:10:51Z",
    "nvd_published_at": "2026-06-19T15:16:35Z",
    "severity": "LOW"
  },
  "details": "### Summary\n\n`AbstractGenerator::$temporaryFiles` is a public array, and `removeTemporaryFiles()` \u2014 invoked from `__destruct()` and from a registered shutdown function \u2014 calls `unlink()` on every entry without verifying that the path is contained within the temporary folder. Any code holding a reference to a generator instance can push an arbitrary path into the array and have it deleted on script shutdown.\n\nThis mirrors the KnpLabs/snappy issue [GHSA-87qc-37cw-84h4](https://github.com/KnpLabs/snappy/security/advisories/GHSA-87qc-37cw-84h4), patched in snappy 1.7.2.\n\n### Affected versions\n\n`pontedilana/php-weasyprint` versions `\u003c= 2.5.1`.\n\nPatched in: `2.6.0`.\n\n### Vulnerable code\n\n`src/AbstractGenerator.php`:\n\n```php\npublic array $temporaryFiles = [];\n\n// ...\n\npublic function removeTemporaryFiles(): void\n{\n    foreach ($this-\u003etemporaryFiles as $file) {\n        $this-\u003eunlink($file);\n    }\n}\n```\n\nNo path-containment check: whatever path is present in `$temporaryFiles` at shutdown is unlinked.\n\n### Proof of concept\n\n```php\n\u003c?php\nuse Pontedilana\\PhpWeasyPrint\\Pdf;\n\n$pdf = new Pdf();\n$pdf-\u003etemporaryFiles[] = \u0027/var/www/html/.env\u0027;\n\n// On shutdown, removeTemporaryFiles() deletes /var/www/html/.env.\n```\n\n### Impact\n\n- Arbitrary file deletion bound to script shutdown, scoped to the privileges of the PHP process user.\n- Not directly exploitable on its own (the attacker already needs to influence the property in the same request). The risk is **amplification**: chained with a separate disclosure bug it enables leak-then-delete-to-cover-tracks, and any deserialization/property-oriented gadget that reaches this property becomes a generic file-delete primitive.\n\nCWE-73 (External Control of File Name or Path).\n\n### Suggested fix\n\nOnly delete files that actually live inside the temporary folder, comparing canonical (`realpath`) paths:\n\n```php\npublic function removeTemporaryFiles(): void\n{\n    $temporaryFolderPath = \\realpath($this-\u003egetTemporaryFolder());\n    if (false === $temporaryFolderPath) {\n        return;\n    }\n    $temporaryFolderPath = \\rtrim($temporaryFolderPath, \\DIRECTORY_SEPARATOR) . \\DIRECTORY_SEPARATOR;\n\n    foreach ($this-\u003etemporaryFiles as $file) {\n        $filePath = \\realpath($file);\n        if (false === $filePath || 0 !== \\strncmp($filePath, $temporaryFolderPath, \\strlen($temporaryFolderPath))) {\n            continue;\n        }\n        $this-\u003eunlink($file);\n    }\n}\n```\n\n(The trailing directory separator prevents a sibling folder such as `/tmpevil` from matching `/tmp`; `strncmp` is used instead of `str_starts_with` to keep PHP 7.4 compatibility.)\n\n### Credit\n\nReported upstream to KnpLabs/snappy ([GHSA-87qc-37cw-84h4](https://github.com/KnpLabs/snappy/security/advisories/GHSA-87qc-37cw-84h4)); identified as applicable to `pontedilana/php-weasyprint`, which mirrors the same code.",
  "id": "GHSA-5g9f-cwwg-4p8g",
  "modified": "2026-06-26T22:10:51Z",
  "published": "2026-06-26T22:10:51Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/KnpLabs/snappy/security/advisories/GHSA-87qc-37cw-84h4"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pontedilana/php-weasyprint/security/advisories/GHSA-5g9f-cwwg-4p8g"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-49358"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pontedilana/php-weasyprint/commit/6d328ffd3bcb800c7c2e8a594b1bff0c099c9391"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pontedilana/php-weasyprint"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pontedilana/php-weasyprint/releases/tag/2.6.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "PhpWeasyPrint vulnerable to arbitrary file deletion at shutdown via public $temporaryFiles"
}


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