Vulnerability · Published May 21, 2026 · Assigned by ConcreteCMS

CVE-2026-7887For Concrete CMS 9.5.0 and below, OAuth 2.0 Authorization-Code Handler Bypasses Account Status

Low 2.3

In plain English

A low-severity security flaw in Concrete CMS from Concrete CMS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)2.3Low

Exploit odds (30 days)0.2%top 93.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

For Concrete CMS 9.5.0 and below, OAuth 2.0 Authorization-Code Handler Bypasses Account Status. A user with uIsActive=0 (suspended, banned, terminated employee) can still authenticate via OAuth and receive valid API tokens. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N. Thanks 0x4c616e for reporting.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	concrete5/concrete5	9.5.1	GHSA-f54h-78c9-c24h

Affected products (as reported)

Vendor	Product	Versions
Concrete CMS	Concrete CMS	5.0 – through 9.5.0

Weakness: CWE-1287 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

References

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