ConcreteCMS is vulnerable to Denial of Service During Bulk Downloads

CVE-2026-30662 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

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 'file_get_contents', 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.

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
—
Source code
Browse source ↗
Published (advisory)
2026-03-24 15:30:29 UTC
Updated
2026-03-26 18:38:50 UTC
GitHub reviewed
2026-03-26 18:38:46 UTC
NVD published
2026-03-24

EPSS Score

Score Percentile
0.04% 13.49%

CVSS Scores

Base score Version Severity Vector
6.5 3.1 —
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type Value
GHSA GHSA-p68c-rmfh-j48h ↗
CVE CVE-2026-30662 ↗

CWEs

CWE id Name
CWE-770 Allocation of Resources Without Limits or Throttling

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
composer concrete5/concrete5 <= 9.4.7 — —

References

cvelogic Threat Intelligence