What is CVE-2026-61449?

CVE-2026-61449 is a medium-severity security vulnerability in getgrav/grav (composer), affecting versions = 2.0.1. It is fixed in 2.0.2.

How severe is CVE-2026-61449?

CVE-2026-61449 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.

Which versions of getgrav/grav are affected by CVE-2026-61449?

getgrav/grav (composer) versions = 2.0.1 is affected.

Is there a fix for CVE-2026-61449?

Yes. CVE-2026-61449 is fixed in 2.0.2. Upgrade to this version or later.

Is CVE-2026-61449 exploitable, and should I be worried?

Whether CVE-2026-61449 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.

What actually determines whether CVE-2026-61449 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.

How do I fix CVE-2026-61449?

Upgrade getgrav/grav to 2.0.2 or later.

CVE-2026-61449 in getgrav/grav

Summary

Grav: Decompression-bomb size cap bypassed by forged ZIP size in ZipArchiver/Installer

The decompression-bomb bound added in 2.0.1 (commit 1c1003c) sums ZipArchive::statIndex($i)['size'] and rejects an archive whose declared uncompressed total exceeds system.gpm.archive.max_uncompressed_size (default 1 GiB) before extracting (ZipArchiver.php:77-86; same logic in GPM\Installer::unZip at Installer.php:228-238). statIndex()['size'] is the uncompressed size declared in the ZIP central directory, which is attacker-forgeable and is not checked against the actual inflated stream. An archive declaring 1 byte per entry passes the cap while extractTo() writes the real (large) content. The entry-count and nesting-depth caps count real structure and still hold; only the size dimension is defeated, so the disk-fill / inode-exhaustion case the bound targets is not prevented. Incomplete fix for GHSA-928x-9mpw-8h56.

Details

extract()/unZip() validate every entry up front, then call Folder::create + extractTo. The size check is:

$totalSize += (int) $stat['size'];          // declared central-directory size
if ($maxSize > 0 && $totalSize > $maxSize) { ... reject ... }

$stat['size'] is read from the central directory, which the archive author writes. libzip does not cross-check declared-vs-actual size during extractTo, so a forged-small value passes the gate and the real stream inflates to disk. The max_files (entry count) and max_depth (entry-name segments) checks are not forgeable this way.

PoC

Build a 10 KiB deflate ZIP of 10 MiB of zeros, patch both uncompressed-size fields (local header + central directory) to 1:

import zipfile, struct
data = b'\x00' * (10*1024*1024)
with zipfile.ZipFile('bomb.zip','w',zipfile.ZIP_DEFLATED) as z:
    z.writestr('big.bin', data)
raw = bytearray(open('bomb.zip','rb').read())
raw = raw.replace(struct.pack('<I', 10*1024*1024), struct.pack('<I', 1))
open('bomb_forged.zip','wb').write(raw)

Drive the exact pre-extraction loop, then extract:

$zip = new ZipArchive(); $zip->open('bomb_forged.zip');
$total = 0;
for ($i = 0; $i < $zip->count(); $i++) { $total += (int) $zip->statIndex($i)['size']; }
// => $total === 1   (what the 1 GiB bound checks: PASSES)
$zip->extractTo('/tmp/zout');
// => filesize('/tmp/zout/big.bin') === 10485760   (written despite the cap)

Verified on Grav 2.0.1 (6f619f0ae), PHP 8.4.22, libzip 1.7.3.

Impact

A forged archive fills the disk / exhausts inodes during extraction. Reached via GPM\Installer::unZip (gpm install / direct-install / self-upgrade) and admin backup restore (ZipArchiver::extract). The archive bytes come from a package source or an admin upload, so the actor sits at admin/operator trust and a consented malicious package already has worse primitives.

CVE-2026-61449 has a CVSS score of 6.5 (Medium). The vector is network-reachable, no privileges required, and user interaction required. 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 (2.0.2); upgrading removes the vulnerable code path.

Affected versions

getgrav/grav (= 2.0.1)

Security releases

getgrav/grav → 2.0.2 (composer)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

ZipArchiver.php:77-86 and Installer.php:228-238: don't trust the declared size. Extract each entry through a counting stream (ZipArchive::getStream + fread loop) and abort once cumulative written bytes pass max_uncompressed_size, leaving nothing on disk; or check on-disk bytes incrementally during extraction. If the pre-pass stays, treat the declared-size sum as advisory and add the streamed byte counter as the real enforcement. max_files and max_depth remain effective.

Frequently Asked Questions

What is CVE-2026-61449? CVE-2026-61449 is a medium-severity security vulnerability in getgrav/grav (composer), affecting versions = 2.0.1. It is fixed in 2.0.2.
How severe is CVE-2026-61449? CVE-2026-61449 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.
Which versions of getgrav/grav are affected by CVE-2026-61449? getgrav/grav (composer) versions = 2.0.1 is affected.
Is there a fix for CVE-2026-61449? Yes. CVE-2026-61449 is fixed in 2.0.2. Upgrade to this version or later.
Is CVE-2026-61449 exploitable, and should I be worried? Whether CVE-2026-61449 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
What actually determines whether CVE-2026-61449 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.
How do I fix CVE-2026-61449? Upgrade getgrav/grav to 2.0.2 or later.