CVE-2026-61690

Grav: Decompression Bomb via ZipArchiver - Missing Extraction Limits

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;
    }
}

// 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);

# 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

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

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.

CVE-2026-61690 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.0.1); upgrading removes the vulnerable code path.

Kodem intelligence

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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;
    }
}

1. What is CVE-2026-61690? CVE-2026-61690 is a medium-severity security vulnerability in getgrav/grav (composer), affecting versions < 2.0.1. It is fixed in 2.0.1.
2. How severe is CVE-2026-61690? CVE-2026-61690 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of getgrav/grav are affected by CVE-2026-61690? getgrav/grav (composer) versions < 2.0.1 is affected.
4. Is there a fix for CVE-2026-61690? Yes. CVE-2026-61690 is fixed in 2.0.1. Upgrade to this version or later.
5. Is CVE-2026-61690 exploitable, and should I be worried? Whether CVE-2026-61690 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-61690 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-61690? Upgrade getgrav/grav to 2.0.1 or later.