CVE-2023-28821 — Concrete CMS (previously concrete5) before 9

Concrete CMS (previously concrete5) before 9.1 did not have a rate limit for password resets.

01What is this vulnerability?

Concrete CMS (previously concrete5) before 9.1 did not have a rate limit for password resets.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-04-28T00:00:00.000Z
• Last modified: 2025-01-30T20:47:58.107Z

09References

• github.com — https://github.com/concretecms/concretecms/releases
• www.concretecms.org — https://www.concretecms.org/about/project-news/security/concrete-cms-security-ad…