TI-2021-17581 Aliases CVE-2021-40555 GHSA-rp7v-crhj-652h

Cross site scripting (XSS) vulnerability in flatCore-CMS 2.2.15 allows attackers to…

MEDIUM 58CWE-79Published 2023-02-16 · Updated 2025-03-19

Key facts

Attack vector: Network
Privileges required: Low
User interaction: Required
Attack complexity: Low
Impact type: Cross-site scripting
Confidentiality · integrity · availability: Low · Low · None
Fix status: No fix listed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-79.

Summary

Cross site scripting (XSS) vulnerability in flatCore-CMS 2.2.15 allows attackers to execute arbitrary code via description field on the new page creation form.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00439 38th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
—	—	all versions	—	No fix listed	CNA

— Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:flatcore:flatcore:2.0.7:::::::*	2.0.7	Vulnerable	flatcore

cpe:2.3:a:flatcore:flatcore:2.0.7:*:*:*:*:*:*:* Versions 2.0.7 Vulnerable ·flatcore

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2021-40555
2026-10-03 Alias added: GHSA-rp7v-crhj-652h

References

Exploit 1

https://github.com/flatCore/flatCore-CMS/issues/56

TI-2019-10413 A CSRF vulnerability was found in flatCore before 1.5, leading to the upload of arbitrary… CVSS 3.0HIGH 8.8
TI-2019-07947 An issue was discovered in flatCore 1.4.7. CVSS 3.0HIGH 7.2
TI-2020-13217 flatCore before 1.5.7 allows upload and execution of a .php file by an admin. CVSS 3.1HIGH 7.2
TI-2021-06201 An issue was discovered in flatCore before 2.0.0 build 139. CVSS 3.1MEDIUM 6.5
TI-2017-06862 Cross site scripting (XSS) vulnerability in pages.edit_form.php in flatCore 1.4.6 allows… CVSS 3.0MEDIUM 6.1
TI-2021-06199 An issue was discovered in flatCore before 2.0.0 build 139. CVSS 3.1MEDIUM 4.9

See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences