# CVE-2026-28281: InstantCMS has Multiple CSRF Vulnerabilities

> Attackers can perform unauthorized actions like granting moderator privileges or modifying posts due to missing CSRF token validation in InstantCMS.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 9 Mar 2026
- **Updated:** 10 Mar 2026
- **Also known as:** GHSA-pp43-262q-h73m

## What is CVE-2026-28281?

CVE-2026-28281 is a high-severity vulnerability in instantsoft icms2, published on 9 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2026-28281?

It affects 1 product.


Products: Instantcms Instantcms.

## How do I fix CVE-2026-28281?

No fix has been published for CVE-2026-28281 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-28281 being exploited?

There is no known exploitation of CVE-2026-28281 in the wild and no public exploit code.

## Other vulnerabilities in instantsoft icms2

- [CVE-2023-4188](https://insights.sbomify.com/CVE-2023-4188/): SQL Injection in instantsoft/icms2 (critical 9.8)
- [CVE-2013-10051](https://insights.sbomify.com/CVE-2013-10051/): InstantCMS <= 1.6 Remote PHP Code Execution (critical 9.3)
- [CVE-2023-4704](https://insights.sbomify.com/CVE-2023-4704/): External Control of System or Configuration Setting in instantsoft/icms2 (high 8.8)
- [CVE-2023-4652](https://insights.sbomify.com/CVE-2023-4652/): Cross-site Scripting (XSS) - Stored in instantsoft/icms2 (medium 6.8)
- [CVE-2024-31212](https://insights.sbomify.com/CVE-2024-31212/): SQL injection in index_chart_data action (medium 6.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-28281 and fix it if it is affected.

What it is: CVE-2026-28281 is a high-severity vulnerability in instantsoft icms2, published on 9 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-28281 in the wild and no public exploit code.

Affected product: instantsoft icms2. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-28281/ (Markdown: https://insights.sbomify.com/CVE-2026-28281/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-28281
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-28281
- OSV: https://osv.dev/vulnerability/CVE-2026-28281

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-28281/
Summaries are generated and may contain mistakes; the official description above is the record.