# CVE-2026-45572: Decidim stored XSS in HTML content blocks

Source: https://junglewise.ai/threats/cve-2026-45572-decidim-stored-xss-in-html-content-blocks  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-06. Updated: 2026-07-13  
License: CC BY 4.0 with a link back

CVE-2026-45572 · Severity: medium · CVSS 4.8 · Published 2026-08-06

Decidim is an open-source participatory democracy platform used by governments and organizations to engage with citizens. A vulnerability in the platform's landing page editor allows administrators to embed malicious scripts that execute in the browsers of visitors. While this requires administrative access to exploit, it could be used by a compromised or malicious staff member to perform unauthorized actions on behalf of site visitors.

Technologies: [decidim-core (RubyGems)](https://junglewise.ai/threats/technologies/decidim-core). Vendors: [RubyGems](https://junglewise.ai/threats/vendors/rubygems).

## Quick answers

**Is CVE-2026-45572 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-45572 being exploited in the wild.

**How severe is CVE-2026-45572?** Medium severity, with a CVSS score of 4.8, published 6 August 2026.

**Which products and versions are affected?** decidim-core (RubyGems) ECOSYSTEM:introduced=0,fixed=0.30.9.

**Is there a fix for CVE-2026-45572?** Yes. decidim-core (RubyGems): upgrade to 0.30.9 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-45572 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-45572?** Check whether you run decidim-core (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- decidim-core (RubyGems): upgrade to 0.30.9 or later

  ```sh
  bundle update decidim-core
  ```


## Technical details

A stored cross-site scripting (XSS) vulnerability exists in Decidim's content block system. The root cause is the use of the `.html_safe` method in `Decidim::ContentBlocks::HtmlCell#html_content` (and related cells like SummaryCell and SectionCell) which renders admin-supplied HTML without a sanitization boundary. An attacker with administrative privileges to edit landing pages can persist arbitrary JavaScript that executes in the context of any user visiting the affected page. The vulnerability has been addressed by replacing `.html_safe` with the `decidim_sanitize_editor_admin` helper to properly neutralize unsafe tags and attributes. Patches are available in versions 0.30.9, 0.31.5, and 0.32.0.

## Affected products

- Decidim decidim-core < 0.30.9, >= 0.31.0.rc1, < 0.31.5, >= 0.32.0.rc1, < 0.32.0

## Identifiers

- CVE-2026-45572
- GHSA-533c-2vh9-4r86

## Timeline

- 2026-03-23: other: Pull request with fix submitted
- 2026-05-07: patched: Fix merged into develop branch
- 2026-07-13: advisory: GitHub Advisory published

## References

- [https://github.com/decidim/decidim/security/advisories/GHSA-533c-2vh9-4r86](https://github.com/decidim/decidim/security/advisories/GHSA-533c-2vh9-4r86)
- [https://github.com/decidim/decidim/pull/16451](https://github.com/decidim/decidim/pull/16451)
- [https://api.github.com/repos/decidim/decidim/security-advisories/GHSA-533c-2vh9-4r86](https://api.github.com/repos/decidim/decidim/security-advisories/GHSA-533c-2vh9-4r86)

## Related threats

- [Decidim decidim-core SSRF in push notification subscriptions](https://junglewise.ai/threats/cve-2026-45573-decidim-decidim-core-ssrf-in-push-notification-subscriptions)
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- [Decidim's private data exports can lead to data leaks](https://junglewise.ai/threats/cve-2025-65017-decidim-s-private-data-exports-can-lead-to-data-leaks)