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CVE-2026-28281

Instantcms cross-site request forgery (CSRF)

7.1 HIGHPublic exploitEPSS 0.17%
  1. Published10 Mar 2026

Description

InstantCMS is a free and open source content management system. Prior to 2.18.1, InstantCMS does not validate CSRF tokens, which allows attackers grant moderator privileges to users, execute scheduled tasks, move posts to trash, and accept friend requests on behalf of the user. This vulnerability is fixed in 2.18.1.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionRequired
ScopeUnchanged
ConfidentialityLow
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N

Affected products

Instantcms< 2.18.1

Remediation

Fixed in
Instantcms≥ 2.18.1

References

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Frequently asked

Is CVE-2026-28281 being actively exploited?

CVE-2026-28281 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.17%.

How severe is CVE-2026-28281?

CVE-2026-28281 has a CVSS 3.1 base score of 7.1, rated high. EPSS estimates a 0.17% probability of exploitation.

Which products are affected by CVE-2026-28281?

Affected products include Instantcms.

How do I fix CVE-2026-28281?

Upgrade affected software to a fixed version, for example Instantcms 2.18.1 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-28281 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.