CVE-2026-8139CWE-79

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

Low · published May 21, 2026

CVSS v4.0
2.0
EPSS
0%
Percentile
15.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
2.0 · LOW
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
EPSS
0.00250 · 15.4th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-05-21T21:45Z
EPSS history
Timeline
  • 21 MAY 21:45Z
    Concrete CMS 9.5.0 and below is vulnerable to Stored XSS via external-link page cvName
    cvelistv5