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NVD / CVE Program· CNA ConcreteCMS

CVE-2026-18422: Concrete CMS below 9.5.3 Multilingual Page Assign Action Lacks Destination Authorization and CSRF Token Validation

Noroxi assessment

Priority: Monitor (action score 8/100)

  • 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: 0.47% (FIRST EPSS).
  • 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.
  • According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

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

Concrete CMS before 9.5.3 did not enforce a destination-side authorization check and did not validate a CSRF token in the multilingual page assignment backend action (Backend\Page\Multilingual::assign). As a result, an authenticated user who held the Edit Page Multilingual Settings permission on a single page could bind an arbitrary page in another locale as that source page's translation, and could delete legitimate translation pairs maintained by other editors, altering public-facing language routing across the site. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.

LowCVSS 2.1 · v4.0—No exploit No fix recorded
Published
Sep 15, 2026
Updated
Sep 21, 2026
EPSS
0.4% · 41th percentile

Report tools

JSON

Action score

8

Monitor

Low priority for now.

CVSS
8 / 40 · 2.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · ConcreteCMS
2.1
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-18422

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

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Affected 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.

VendorProduct
concretecmsconcrete 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 9.5.3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (ConcreteCMS). Independent of NVD's CPE analysis and usually ahead of it.

  • Concrete CMS Concrete CMS

    • 5.0.0 and later · up to and including 9.5.2affected · git

Same product

concretecms: all records

Other 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 controller
    60This 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 c
    40Plan
  • 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-2026-81923Sep 15, 2026 · Concrete CMS below 9.5.3 is missing authorization in the SEO Bulk Update Meta Tags editor
    8Monitor
  • ← EarlierCVE-2026-81924Sep 15, 2026 · Concrete CMS below 9.5.3 is vulnerable to Cross-Site Request Forgery (CSRF) in Theme Page Template Activation
    8Monitor
  • Later →CVE-2026-18423Sep 15, 2026 · Concrete CMS 9.0.0 through 9.5.2 is vulnerable to Insecure direct object reference (IDOR) in the Express saved search preset delete and edit dialogs allowing a
    8Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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 researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-181100 days apartConcrete CMS 9.0.0 through 9.5.2 is vulnerable to missing authorization in the user selector autocomplete endpoint (/ccm/system/user/autocomplete), allowing an
    34Monitor
  • CVE-2026-819011 days apartConcrete CMS 9.2.0 to 9.5.2 is vulnerable to stored XSS due to missing authorization in the `PUT /pages/{cID}` endpoint
    28Monitor
  • CVE-2026-181201 days apartMissing Authorization in legacy Express entries search endpoint allows disclosure of Express entry data
    25Monitor
  • CVE-2026-7879117 days apartConcrete CMS 9.5.0 and below is vulnerable to File Download Authorization Bypass in submit_password()
    25Monitor
  • CVE-2026-8237117 days apartConcrete CMS 9.5.0 and below is vulnerable to IDOR in the`/ccm/frontend/conversations/message_detail` endpoint
    25Monitor
  • CVE-2026-8239117 days apartConcrete CMS 9.5.0 and below is vulnerable to IDOR in '/ccm/frontend/conversations/get_rating'
    25Monitor

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
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
X

Weakness class (CWE)

CWE-862 · Missing Authorization

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records