CVE-2026-81913Concrete CMS versions 9.5.0 through 9.5.2 are vulnerable to Open Redirect via the rcURL parameter.
Updated under an hour ago ()
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It affects Concrete CMS and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Concrete CMS versions 9.5.0 through 9.5.2 are vulnerable to Open Redirect via the rcURL parameter. An attacker can craft a single link on the site's own domain that sends a user to an arbitrary external site immediately after authentication, facilitating phishing and credential theft. The same handling is present in the registration flow, giving a second entry point on sites with registration enabled. Concrete CMS versions prior to 9.5.0 do not include the rcURL parameter or this allowlist and are not affected. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.3 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Michal M. for reporting.
- CVSS
- 5.3 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-601
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- ConcreteCMS
- NVD analysis
- Analyzed
- Record last updated
- Sep 11, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Concrete CMS Concrete CMS concrete_cms:concrete_cms (from the name) | from 9.5.0 through 9.5.2 | CNA record |
concretecms concrete_cms concretecms:concrete_cms | from 9.5.0 before 9.5.3 | NVD |
References
- https://documentation.concretecms.org/developers/introduction/version-history/953-release-notesrelease-notes, broken-link
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.