CVE-2026-56290Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0
- 10.0CriticalCVSS base score
- 30.9%Exploitation in 30 daysEPSS · top 1.7% of all CVEs
- YesKnown exploitedin CISA's KEV since 7 Jul 2026
- 2Public exploitsMetasploit, Nuclei and Exploit-DB
Description
Joomla Extension - joomlack.fr - Unauthenticated file upload in Page Builder CK extension < 3.6.0 - The Joomla extension Page Builder CK is vulnerable to an unauthenticated arbitrary file upload that allows uploading executable files and leads to full RCE.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Joomlack Page Builder Improper Access Control Vulnerability.
- Added
- 7 Jul 2026
- Fix due (US federal)
- 10 Jul 2026
- Used by ransomware
- Not known
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
ENISA's EU Vulnerability Database lists it as exploited, from CISA's KEV, since 7 Jul 2026.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. The public collections list a Nuclei template and an Exploit-DB entry for it. CISA's SSVC rates its exploitation: it is being exploited.
Show the exploits2
Nuclei templates1 template
- Page Builder CK <= 3.5.10 - Unauthenticated Arbitrary File Upload (Nuclei template) (opens in a new tab)
http/cves/2026/CVE-2026-56290.yamlSeverity critical
Exploit-DB1 entry
- Joomla Page Builder CK 3.5.10 - Arbitrary File Upload (Exploit-DB entry) (opens in a new tab)
EDB-ID 52626webapps, multiplepublished 8 Jul 2026Not verified
Modules, templates and exploits as listed by the Metasploit Framework (BSD-3-Clause), ProjectDiscovery's Nuclei templates (MIT) and the Exploit Database (GPLv2), read once a day. Where the data comes from
Timeline
ID reserved
By Joomla
- 9 days later
· 9 days later
Published
- 8 days later
· 8 days later
Added to CISA KEV
Known exploited in the wild
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| JoomlaCNA (assigner) | 4.0 | Critical10.0 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/AU:Y/U:Red |
| NVDNVD · Analyzed | 4.0 | Critical10.0 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:A/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:Y/R:X/V:X/RE:X/U:Red |
- EPSS (exploitation in 30 days)
- 30.9% · top 1.7% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 10.0.
Affected products
joomlack.fr · JoomlaCK.fr Page Builder CK extension for Joomla
- affected 1.0-3.6.0
References
References4
- https://www.joomlack.fr/ (opens in a new tab)product
- https://mysites.guru/blog/pagebuilderck-unauthenticated-file-upload-rce/ (opens in a new tab)third-party-advisory
- https://forum.joomlack.fr/index.php/page-builder-ck/21627-nouvelle-version-de-pbck-et-joomla-3 (opens in a new tab)patch
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-56290 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-40121 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-56290)Record last updated .