CVE-2021-22968: A bypass of adding remote files in Concrete CMS (previously concrete5) File Manager leads to remote code execution in Concrete CMS (concrete
Noroxi assessment
Priority: Monitor (action score 29/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 3.2% (FIRST EPSS); higher than 88.3% of all records.
- Anyone who can reach it over the internet can trigger it. Administrator privileges are required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: concrete5/core (Packagist) 8.5.7.
Low priority for now. Upgrade to concrete5/core (Packagist) 8.5.7 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
A bypass of adding remote files in Concrete CMS (previously concrete5) File Manager leads to remote code execution in Concrete CMS (concrete5) versions 8.5.6 and below.The external file upload feature stages files in the public directory even if they have disallowed file extensions. They are stored in a directory with a random name, but it's possible to stall the uploads and brute force the directory name. You have to be an admin with the ability to upload files, but this bug gives you the ability to upload restricted file types and execute them depending on server configuration.To fix this, a check for allowed file extensions was added before downloading files to a tmp directory.Concrete CMS Security Team gave this a CVSS v3.1 score of 5.4 AV:N/AC:H/PR:H/UI:R/S:C/C:N/I:H/A:NThis fix is also in Concrete version 9.0.0
- Published
- Nov 19, 2021
- Updated
- Jun 16, 2026
- EPSS
- 3.2% · 88th percentile
- CWE
- CWE-98
Report tools
Action score
29
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.2 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 3.2%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| concretecms | concrete cms | cpe:2.3:a:concretecms:concrete_cms |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- concretecms concrete cmsbefore 8.5.7
Versions reported by the vendor
Affected version ranges reported by the assigning authority (hackerone). Independent of NVD's CPE analysis and usually ahead of it.
n/a https://github.com/concrete5/concrete5
- Concrete CMS version 9.0 and version 8.5.7affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Packagist | concrete5/core | before 8.5.7 | 8.5.7 |
Same product
concretecms: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-6826Concrete 9.5.0 and below has file usage disclosure via missing permission check in Usage controller60This week
- CVE-2022-21829Concrete CMS Versions 9.0.0 through 9.0.2 and 8.5.7 and below can download zip files over HTTP and execute code from those zip files which c40Plan
- CVE-2023-48648Concrete CMS before 8.5.13 and 9.x before 9.2.2 allows unauthorized access because directories can be created with insecure permissions.39Monitor
Published before and after this one in the same product
- ← EarlierCVE-2021-22966Nov 19, 2021 · Privilege escalation from Editor to Admin using Groups in Concrete CMS versions 8.5.6 and below.35Monitor
- ← EarlierCVE-2021-22967Nov 19, 2021 · In Concrete CMS (formerly concrete 5) below 8.5.7, IDOR Allows Unauthenticated User to Access Restricted Files If Allowed to Add Message to 30Monitor
- Later →CVE-2021-22969Nov 19, 2021 · Concrete CMS (formerly concrete5) versions below 8.5.7 has a SSRF mitigation bypass using DNS Rebind attack giving an attacker the ability t21Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Packagist:concrete5/core | 8.5.7 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- Administrator privileges are required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-98 · Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
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Change log
- Fix✗ → ✓
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References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.