CVE-2026-86730 json
Craft CMS 5.0.0-RC1 before 5.10.12 Behavior Injection RCE
published 2mo ago modified 2mo ago also EUVD-2026-72866 , GHSA-qj4v-m29p-fj4m
Unreviewed: the maintainers' own advisory
Published by the maintainers on their GitHub repository craftcms/cms. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.
- cvss
- 8.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 53%
- public exploits
- 0
- none known
Summary
Craft CMS versions before 5.10.12 fail to properly cleanse string-typed field-layout elements, allowing authenticated control-panel users to inject Yii2 behavior attachments and event handlers. Attackers can post field-layout tab elements as JSON strings to bypass cleanse validation, then trigger arbitrary object instantiation and code execution through Craft::createObject().
Patch / fix
- craftcms cms 5.10.12
Is CVE-2026-86730 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 2mo ago
Exploit prediction
0.71% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| CNA | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| CNA | 4.0 | 8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/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 | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected products
- craftcms cms
Classification
- Weakness
-
- CWE-94 Improper Control of Generation of Code
References
-
github.com
/craftcms/cms/security/advisories/GHSA-qj4v-m29p-fj4m
vendor-advisory, advisory
-
vulncheck.com
/advisories/craft-cms-5.0.0-rc1-before-5.10.12-behavior-injection-rce
third-party-advisory
Sources
- CVE List CVE-2026-86730
- NVD CVE-2026-86730
- Maintainer advisory GHSA-qj4v-m29p-fj4m
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
The maintainers of craftcms/cms published their own advisory on GitHub. Reviewed sources take precedence over it.