CVE-2026-8239

mediumpriority · track · 31OT risk · elevatedEPSS 0.003 · 24 %ileexploit · PoCEUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

1 exploit · PoC

Likely / severe?

0.33% (24th) EPSS

CVSS 5.3 · medium

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-22

Concrete CMS 9.5.0 and below is vulnerable to IDOR. The '/ccm/frontend/conversations/get_rating' endpoint confirms existence and returns rating score for any message by ID. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 6.3 with Vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Tristan Madani for reporting.

cvss

Technical severity, 0–10. One row per scoring source.

6.3

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 2.9–6.3

v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 1.4

v4.06.3mediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:Nsecondary · ENISA EU

v4.06.3mediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/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:Xsecondary

v4.02.9lowCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/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:Xsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-862USCWE-862US

exploits (1)

Public proof-of-concept and weaponised exploit code.

aj2108/CVE-2026-8239CVE-2026-8239 is an Insecure Direct Object Reference (IDOR) vulnerability affecting Concrete CMS 9.5.0 and earlier.PoC · poc_in_github

affected products (3)

Products and version ranges known to be affected.

Concrete CMS Concrete CMS≤ 5.0 ≤9.5.0enisa_euvdEU
concretecms concrete cms< 9.5.1nvdUScpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*
Packagist concrete5/concrete5< 9.5.1osvUSpkg:composer/concrete5/concrete5

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-2xp7-rpvc-pjwcConcrete CMS is vulnerable to IDOR2026-05-22ghsa · osvUS
Concrete CMS 9.5.0 and below is vulnerable to IDOR. The '/ccm/frontend/conversations/get_rating' endpoint confirms existence and returns rating score for any message by ID.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2026-05-21modified 2026-07-23

references (4)

External citations — patches, advisories, analysis.

scry

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