CVE-2026-8139 PUBLISHED

Concrete CMS 9.5.0 and below is vulnerable to Stored XSS via external-link page cvName

Assigner: ConcreteCMS
Reserved: 07.05.2026 Published: 21.05.2026 Updated: 22.05.2026

Concrete CMS 9.5.0 and below is vulnerable to Stored XSS via external-link page cvName because updateCollectionAliasExternal bypasses being sanitized. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.0 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori (Tenzai) for reporting.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
CVSS Score: 2

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	Low	Confidentiality	None
Attack Complexity	Low	Integrity	Low	Integrity	None
Attack Requirements	Present	Availability	None	Availability	None
Privileges Required	High
User Interaction	Passive

CVSS 4.0

Product Status

Vendor	Concrete CMS
Product	Concrete CMS
Versions	Default: unaffected affected from 5.0 to 9.5.0 (incl.)

References

https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes

Problem Types

CWE-79 Improper neutralization of input during web page generation ('cross-site scripting') CWE

Impacts

CAPEC-592 Stored XSS