CVE-2026-81916

MEDIUMCVSS 4.3/10EPSS 0.28%

Last modified

CVE-2026-81916 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. Concrete CMS before 9.5.3 evaluated the authorization check for an Express entry submission against the entity of the posted form rather than the entity identified by the dashboard route. As a result, a user permitted to add entries to one Express object could create entries in a different Express object outside their authorization scope, potentially polluting protected datasets, triggering workflows, or injecting content into administrative processes. EPSS estimates a 0.28% chance of exploitation in the next 30 days.

Description

Concrete CMS before 9.5.3 evaluated the authorization check for an Express entry submission against the entity of the posted form rather than the entity identified by the dashboard route. As a result, a user permitted to add entries to one Express object could create entries in a different Express object outside their authorization scope, potentially polluting protected datasets, triggering workflows, or injecting content into administrative processes. The dashboard submit route resolved the mutated entity from the attacker-controlled route ID while the permission check validated the independently posted form's entity, and the submission proceeded because the two entities were never compared. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.1 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.

Metrics

Weakness Enumeration

Affected Software

VendorProductVersions
ConcretecmsConcrete Cms< 9.5.3

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-81916?
Concrete CMS before 9.5.3 evaluated the authorization check for an Express entry submission against the entity of the posted form rather than the entity identified by the dashboard route. As a result, a user permitted to add entries to one Express object could create entries in a different Express object outside their authorization scope, potentially polluting protected datasets, triggering workflows, or injecting content into administrative processes. The dashboard submit route resolved the mutated entity from the attacker-controlled route ID while the permission check validated the independently posted form's entity, and the submission proceeded because the two entities were never compared. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.1 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.
How severe is CVE-2026-81916?
CVE-2026-81916 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.28% probability of exploitation in the next 30 days.
How do I fix CVE-2026-81916?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST