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CVE-2026-45377 medium CVSS 6.5

Information Disclosure in decidim-core (CVE-2026-45377)

Summary

Vulnerability in decidim-core (CVE-2026-45377). Confidential information can be exposed externally. Exploitable via download_your_data. Mitigation: upgrade to 0.32.0 or later.

Original description

The description as published by the source.

Description

The normal download_your_data flow requires the requester to be logged in as the export owner, but the resulting Active Storage blob redirect URL can be replayed without authentication by anyone who obtains it.

Technical description

This private export flow turns an authenticated, user-scoped download into a reusable bearer link because the protected Decidim endpoint redirects to the underlying Active Storage blob URL. Decidim::DownloadYourDataController#download_file correctly scopes the export record to current_user, so the wrapper route itself is not directly accessible to another user. However, once the owner
performs that authenticated GET request, the response redirects to a signed Active Storage URL that is no longer bound to the user session. Anyone who learns that URL can replay it and retrieve the file without being logged in as the export owner.

Because the blob redirect URL is delivered through a GET request and appears in the redirect chain, it is more likely to leak through browser history, logs, proxy tooling, screenshots, copied links, support transcripts, or other client-side handling of URLs.

Reproduction steps:

Step 1. Generate or locate a completed export in the Web UI.

  1. Sign in as user@example.org at http://localhost:3001/users/sign_in.
  2. Open http://localhost:3001/download_your_data.
  3. Request a new export from the page and wait until the export becomes downloadable.
  4. Open the completed export entry from the lis…

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-2026-45377 has been found in decidim-core.
Attackers can target a specific entry point like download_your_data over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 6.5/10.
What to do: upgrade decidim-core to 0.32.0 or later.
If unsure, ask your IT team or search "decidim-core CVE-2026-45377" on the vendor's site.

CVE-2026-45377 (decidim-core) — CWE-200 / CVSS v3 6.5
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: download_your_data / current_user
Patched: 0.32.0 — apply immediately
Workaround: Disable Private Downloads URLs
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.

❓ What is the problem

Information disclosure (CWE-200) exists in decidim-core. Attackers reach the vulnerable code path via download_your_data without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of decidim-core. Attack surface: download_your_data / current_user.

🔥 Severity

Severity: Medium (CVSS 6.5/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 0.32.0.

🛡️ Workaround

Workaround: Disable Private Downloads URLs

🔍 Detection

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

  1. 1
    Identify 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。

  2. 2
    Apply temporary workaround mitigate 
    Disable Private Downloads URLs

    パッチが適用されるまでの応急処置として、Disable Private Downloads URLs を実施。回避策の副作用 (機能低下) を確認した上で。

  3. 3
    Apply 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。

  4. 4
    Post-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

rubygems decidim-core
[{"type":"ECOSYSTEM","events":[{"introduced":"0.32.0.rc1"},{"fixed":"0.32.0"}]}]

References

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