CVE-2026-68535 — Missing Authorization in Concretecms Concrete Cms
Concrete CMS Area API's block-create endpoint in versions 9.2.0 to 9.5.2 did not invoke the block type controller's validate() method on submitted data, which, for file-referencing blocks such as hero_image and gallery, is where the referenced file is authorized against the user's file-manager visibility. As a result, an authenticated user holding the block-add scope could store, and cause the page to render, a reference to a file that the file-manager authorization policy would otherwise reject, disclosing that file's URL and preview to the editor and to visitors of the affected page. Under public file storage, the URL and thumbnail are exposed directly; under private storage, the disclosure is limited by the permission-checked download URL. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.1 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N. Thanks riodrwn for reporting.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (medium)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Concretecms Concrete Cms).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Concretecms | Concrete Cms | ≥ 9.2.0 and < 9.5.3 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.1 | CVSS 4.0 | Medium | — | — | ff5b8ace-8b95-4078-9743-eac1ca5451de via NIST National Vulnerability Database |
| 4.3 | CVSS 3.1 | Medium | 2.8 | 1.4 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Audit administrative actions and access to resources outside each user’s normal pattern.
Timeline
What happened to this CVE, newest first.
- 2026
- Record published
- CVSS changed · 4.3
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-85387 Concrete CMS before 9.5.4 re-authorized OAuth REST API requests from the bearer token… 29d
- Medium CVE-2026-18120 Missing Authorization in Concretecms Concrete Cms 29d
- Low CVE-2026-87031 Missing Authorization in Concretecms Concrete Cms 29d
- Medium CVE-2026-87028 Missing Authorization in Concretecms Concrete Cms 29d
- Critical CVE-2026-85385 Cross-site Scripting (XSS) in Concretecms Concrete Cms 29d
- Medium CVE-2026-85386 Cross-site Scripting (XSS) in Concretecms Concrete Cms 29d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No CISA SSVC assessment.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-68535 is "Missing Authorization in Concretecms Concrete Cms", rated Medium. It affects Concrete Cms (Concretecms); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.3 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
Comments
Moderated technical discussion. Read the community guidelines.
No comments yet.
Sign in or create an account to comment and suggest corrections.