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Medium, CVSS 6.5

ConcreteCMS is vulnerable to Denial of Service During Bulk Downloads

CVE-2026-30662GHSA-p68c-rmfh-j48h

What to do

Vendor response not established. Follow the primary source's mitigation guidance and check back for a fix.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • Packagist concrete5/concrete5

    Affected
    <= 9.4.7
    Fixed in
    no fixed version recorded

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS
  • CVE-2026-30662: 0.30% estimated exploitation activity in the next 30 days; percentile 22.70 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

ConcreteCMS v9.4.7 contains a Denial of Service (DoS) vulnerability in the File Manager component. The 'download' method in 'concrete/controllers/backend/file.php' improperly manages memory when creating zip archives. It uses 'ZipArchive::addFromString' combined with 'filegetcontents', which loads the entire content of every selected file into PHP memory. An authenticated attacker can exploit this by requesting a bulk download of large files, triggering an Out-Of-Memory (OOM) condition that causes the PHP-FPM process to terminate (SIGSEGV) and the web server to return a 500 error.

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-p68c-rmfh-j48h

Agent brief

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# Patch Next advisory brief: CVE-2026-30662

Advisory: ConcreteCMS is vulnerable to Denial of Service During Bulk Downloads
IDs: CVE-2026-30662, GHSA-p68c-rmfh-j48h
Record: https://patchnext.com/advisories/cve-2026-30662 (revision 1, source checked 26 Oct 2026, 14:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist concrete5/concrete5: affected <= 9.4.7

## Suggested inspection (read-only)
- Packagist concrete5/concrete5: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on concrete5/concrete5.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-p68c-rmfh-j48h (GitHub-reviewed advisory GHSA-p68c-rmfh-j48h lists affected ranges: Packagist concrete5/concrete5 >=0 <=9.4.7)

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