Code Injection in decidim-core (CVE-2026-45572)
Summary
Code injection in decidim-core (CVE-2026-45572). Risk of unauthorized operations or information disclosure. Exploitable via html_safe. Mitigation: upgrade to 0.32.0 or later.
Original description
The description as published by the source.
Description
A privileged admin user who can edit an affected landing page can store arbitrary HTML/JavaScript in an HTML block, and the public page renders it with html_safe and no output escaping.
Technical description
This issue lets any admin who can edit an affected landing page store arbitrary HTML and JavaScript in an HTML block. The block is then rendered back through Decidim::ContentBlocks::HtmlCell#html_content without a sanitization boundary, so the script executes later in visitor's browsers.
Impact
- A user with landing-page editing rights for an affected scope can persist JavaScript that executes in visitor's browsers on that page.
- Because exploitation already requires privileged administrative access, the practical risk is lower than a participant-controlled or unauthenticated stored XSS. It still creates a browser-execution primitive in a trusted admin-editable surface.
Patches
See https://github.com/decidim/decidim/pull/16451
Workarounds
Do not give admin permissions to non-trustful users.
Reference
Stored XSS
Credits
This issue was discovered in a security audit organized by the Decidim Association and made by Radically Open Security against Decidim financed by NGI.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-45572 has been found in decidim-core.
Attackers can target a specific entry point like html_safe over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 4.8/10.
What to do: upgrade decidim-core to 0.32.0 or later.
If unsure, ask your IT team or search "decidim-core CVE-2026-45572" on the vendor's site.
CVE-2026-45572 (decidim-core) — CWE-94 / CVSS v3 4.8
Attack vector: remote (network-reachable)
Attack surface: html_safe
Patched: 0.32.0 — apply immediately
Workaround: Do not give admin permissions to non-trustful users.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Arbitrary code execution (CWE-94) exists in decidim-core. Attackers reach the vulnerable code path via html_safe.
Check the vendor advisory for the affected versions of decidim-core. Attack surface: html_safe.
Severity: Medium (CVSS 4.8/10). Risk of unauthorized operations or information disclosure.
Update to 0.32.0.
Workaround: Do not give admin permissions to non-trustful users.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'decidim-core' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'decidim-core' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
decidim-coreを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
Do not give admin permissions to non-trustful users.パッチが適用されるまでの応急処置として、Do not give admin permissions to non-trustful users. を実施。回避策の副作用 (機能低下) を確認した上で。
-
3Apply patch patch
Upgrade decidim-core to 0.32.0ステージング環境で 0.32.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
4Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- package github.com
- web github.com
- web github.com
- web github.com