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NVD / CVE Program· CNA ConcreteCMS

CVE-2026-68533: Missing Authorization in Concrete CMS versions below 9.5.3 Conversation File Upload Allows File Import Without the Add Message Attachments Permission

Noroxi assessment

Priority: Monitor (action score 9/100)

  • 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: 0.39% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. 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 below 9.5.3 conversation attachment uploaded endpoint imported files into the file manager before evaluating the "Add Message Attachments" permission, which was only checked after the file had been stored. A user denied that permission, or an unauthenticated visitor on a guest-posting configuration, could import approved files of allowed types into the file manager. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N. Thanks riodrwn for reporting.

LowCVSS 2.3 · v4.0—No exploit No fix recorded
Published
Sep 15, 2026
Updated
Sep 16, 2026
EPSS
0.3% · 33th percentile

Report tools

JSON

Action score

9

Monitor

Low priority for now.

CVSS
9 / 40 · 2.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · ConcreteCMS
2.3
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/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-2026-68533

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.

—

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

concrete cms: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-10721Concrete CMS below 9.5.2 is vulnerable to PHP Object Injection via unserialize() calls in the in Permission, Cache, and Search components
    33Monitor
  • CVE-2026-7888Concrete CMS below 9.5.3 is vulnerable to PHP Object Injection via unserialize() calls in the Workflow, Form block, and File/Set components that lack the allowe
    33Monitor
  • CVE-2026-81898Concrete CMS below version 9.5.3 is vulnerable to Stored XSS via country-less Address attribute in Express association views
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-68531Sep 15, 2026 · Concrete CMS below 9.5.3 is vulnerable to Authenticated Denial of Service via Unescaped SQL LIKE Wildcards in Keyword Search
    8Monitor
  • ← EarlierCVE-2026-68532Sep 15, 2026 · Concrete CMS 9.0.0 to 9.5.2 is vunerable to CSRF in Concrete CMS Group Type Deletion Dashboard Action
    9Monitor
  • Later →CVE-2026-68534Sep 15, 2026 · Concrete CMS below 9.5.2 is vulnerable to Stored XSS via unescaped Express entry labels in association selectors
    9Monitor

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-2026-181150 days apartIn Concrete CMS 9.2.0 to 9.5.2, Missing Authorization in REST API Users update() and change_password Enables Account Takeover.
    29Monitor
  • CVE-2026-819047 days apartConcrete CMS before 9.5.3 is vulnerable to Missing Authorization in Stack/Container Sub-Block Asset Registration
    25Monitor
  • CVE-2026-181224 days apartConcrete CMS 9.2.0 to 9.5.2 Express REST API list endpoint exposes restricted Express entries via Missing Authorization
    24Monitor
  • CVE-2026-819084 days apartMissing Authorization in Concrete CMS 9.2.0 to 9.5.2 REST API Groups List Endpoint Allows Authenticated Users to Enumerate All Groups
    24Monitor
  • CVE-2026-819094 days apartConcrete CMS 9 through 9.5.2 is vulnerable to Missing Authorization in the orphaned-block alias route, allowing an authenticated editor to disclose and force-de
    23Monitor
  • CVE-2026-685290 days apartConcrete CMS 9.0.0 through 9.5.2 us missing authorization in the Express entries advanced-search dashboard action allowing a low-privileged user to read other
    8Monitor

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

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • 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
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-862 · Missing Authorization

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/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