CVE Explorer
CVE-2026-8135
Concrete CMS 9.5.0 and below is vulnerable to Remote Code Execution due to insecure deserialization occurring in the ExpressEntryList block controller. An rogue administrator with privileges to add blocks to an area can bypass the intended protection mechanism (_fromCIF === true), which normally restricts malicious inputs over form POST requests, by leveraging the REST API functionality. Because the REST API parses requests using json_decode(), the string "true" is evaluated as a strict PHP Boo
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"collectionURL":"https://github.com/concretecms/concretecms","defaultStatus":"unaffected","product":"Concrete CMS","repo":"https://github.com/concretecms/concretecms","vendor":"Concrete CMS","versions":[{"lessThanOrEqual":"9.5.0","status":"affected","version":"5.0","versionType":"git"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:8efe37d5c39a00699344711d974684bc7b56a91d266e9348b2524c3fcc72d54e · sha256:4a843d1baad73111… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"HIGH","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":8.9,"baseSeverity":"HIGH","exploitMaturity":"NOT_DEFINED","privilegesRequired":"HIGH","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"HIGH","subConfidentialityImpact":"HIGH","subIntegrityImpact":"HIGH","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpac…
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:8efe37d5c39a00699344711d974684bc7b56a91d266e9348b2524c3fcc72d54e · sha256:4a843d1baad73111… · /containers/cna/metrics/0/cvssV4_0
CWE assertions
1 source assertion{"cweId":"CWE-502","description":"CWE-502 Deserialization of untrusted data","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:8efe37d5c39a00699344711d974684bc7b56a91d266e9348b2524c3fcc72d54e · sha256:4a843d1baad73111… · /containers/cna/problemTypes/0/descriptions/0
Source references
1 source assertion{"tags":["release-notes"],"url":"https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:8efe37d5c39a00699344711d974684bc7b56a91d266e9348b2524c3fcc72d54e · sha256:4a843d1baad73111… · /containers/cna/references/0
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.