How severe is CVE-2026-28281?

CVE-2026-28281 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity high, and availability none.

Is CVE-2026-28281 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-28281?

CVE-2026-28281 affects Instantcms. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-28281?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-28281 have an EU (EUVD) identifier?

Yes. CVE-2026-28281 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10405.

When was CVE-2026-28281 published?

CVE-2026-28281 was published on 2026-03-10 and last updated on 2026-06-17.

CVE-2026-28281

CVE-2026-28281 is a high-severity vulnerability in Instantcms with a CVSS 3.x base score of 7.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-352.

Key facts

Severity: High (CVSS 3.x base score 7.1)
EPSS exploit prediction: 0% (3rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-10405
Weakness: CWE-352
Affected product: Instantcms
Published: 2026-03-10
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-28281?: 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.
How severe is CVE-2026-28281?: CVE-2026-28281 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity high, and availability none.
Is CVE-2026-28281 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-28281?: CVE-2026-28281 affects Instantcms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-28281?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-28281 have an EU (EUVD) identifier?: Yes. CVE-2026-28281 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10405.
When was CVE-2026-28281 published?: CVE-2026-28281 was published on 2026-03-10 and last updated on 2026-06-17.

References

https://github.com/instantsoft/icms2/security/advisories/GHSA-pp43-262q-h73m

Affected products (1)

cpe:2.3:a:instantcms:instantcms:*:*:*:*:*:*:*:*

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