# CVE-2026-45572: Decidim: HTML content blocks allow stored script execution

> Administrators can inject malicious scripts into HTML content blocks, leading to stored XSS execution in visitors' browsers.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 6 Aug 2026
- **Updated:** 7 Aug 2026
- **Also known as:** GHSA-533c-2vh9-4r86

## What is CVE-2026-45572?

CVE-2026-45572 is a medium-severity cross-site scripting vulnerability in decidim, published on 6 Aug 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

Decidim is a participatory democracy framework. Prior to 0.30.9, from 0.31.0 before 0.31.5, and in 0.32.0.rc1 before 0.32.0.rc2, an administrator with landing-page editing privileges can store arbitrary HTML and JavaScript in an HTML content block, which Decidim::ContentBlocks::HtmlCell#html_content renders without sanitization, causing the script to execute in visitors' browsers. This issue is fixed in versions 0.30.9, 0.31.5, and 0.32.0.rc2.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2026-45572?

6 open source packages ship an affected version, including decidim-core.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `decidim-core` | RubyGems | All versions | 0.30.9 |
| `decidim-core` | RubyGems | All versions | 0.30.9 |
| `decidim-core` | RubyGems | From 0.31.0.rc1 | 0.31.5 |
| `decidim-core` | RubyGems | From 0.31.0.rc1 | 0.31.5 |
| `decidim-core` | RubyGems | From 0.32.0.rc1 | 0.32.0 |
| `decidim-core` | RubyGems | From 0.32.0.rc1 | 0.32.0 |

## How do I fix CVE-2026-45572?

Upgrade decidim-core to a fixed version for your release line: 0.30.9, 0.31.5 or 0.32.0.

## Is CVE-2026-45572 being exploited?

There is no known exploitation of CVE-2026-45572 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45572 and fix it if it is affected.

What it is: CVE-2026-45572 is a medium-severity cross-site scripting vulnerability in decidim, published on 6 Aug 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-45572 in the wild and no public exploit code.

Affected packages and fixed versions:
- decidim-core (RubyGems): affected all versions; fixed in 0.30.9
- decidim-core (RubyGems): affected all versions; fixed in 0.30.9
- decidim-core (RubyGems): affected from 0.31.0.rc1; fixed in 0.31.5
- decidim-core (RubyGems): affected from 0.31.0.rc1; fixed in 0.31.5
- decidim-core (RubyGems): affected from 0.32.0.rc1; fixed in 0.32.0
- decidim-core (RubyGems): affected from 0.32.0.rc1; fixed in 0.32.0

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-2026-45572/ (Markdown: https://insights.sbomify.com/CVE-2026-45572/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45572
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45572
- OSV: https://osv.dev/vulnerability/CVE-2026-45572

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45572/
Summaries are generated and may contain mistakes; the official description above is the record.