GHSA-3mvf-82qp-8qh5 is a high-severity (CVSS 7.5) Information Exposure vulnerability in decidim-verifications. A fix is available for decidim-verifications — see the affected versions and patch details below.
Decidim: Verification documents can be downloaded through reusable links
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for GHSA-3mvf-82qp-8qh5.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-3mvf-82qp-8qh5 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
decidim-verifications💎decidim-verifications💎decidim-verificationsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Description
Scanned identity-document images provided by participants and shown in the verification admin workflow are exposed through signed /rails/active_storage/disk/ URLs that can be fetched without any authenticated session.
Anyone who obtains one of those URLs can retrieve the document until the signature expires.
Technical description
This issue comes from the verification admin UI exposing scanned documents through reusable Active Storage disk links. Verification-document images are rendered with variant_url(...), which produces signed /rails/active_storage/disk/... links instead of routing the file through an authorization-checking controller. Because Decidim configures Active Storage service URLs to remain valid for seven days, the URL itself becomes the credential for that period.
The affected files are verification_attachment blobs on Decidim::Authorization, and the admin review pages embed those signed URLs directly into the HTML for pending and confirmation views.
Reproduction steps:
-
Create a fresh verification document as a normal user. 1.1. Open http://localhost:3001/users/sign_in. 1.2. Open http://localhost:3001/id_documents/authorizations/new. 1.3. Submit an id_documents verification request with an image attachment.
-
Open the admin review page that renders the attachment. 2.1. Sign out. 2.2. Sign back in as [email protected]. 2.3. Try http://localhost:3001/admin/id_documents.
-
Harvest the signed Active Storage URL. 3.1. Open DevTools Network before loading the review page. 3.2. Reload the page. 3.3. Copy one request URL matching
http://localhost:3001/rails/active_storage/disk/<SIGNED_TOKEN>/<FILENAME>. -
Replay the file URL without any Decidim session. 4.1. Open a private window or a second browser where you are not signed in to Decidim. 4.2. Paste the exact copied /rails/active_storage/disk/... URL. 4.3. Confirm the verification image still loads.
Impact
- This only applies to Organizations using the "Identity documents" verification
- Any party that obtains one of these URLs can download the underlying scanned identity document for the lifetime of the signed link without needing to authenticate as the reviewing admin.
- In the reproduced case, that replay window was about seven days, which is long enough for routine leakage channels such as copied links, screenshots, logs, browser history, and support workflows to become realistic exfiltration paths.
- This raises the risk of leakage through browser history, screenshots, copy-paste, support tickets, logs, analytics tooling, malicious browser extensions, or any other channel that captures full URLs.
- Because the affected files are identity-verification documents, the exposed data can include highly sensitive personal information.
Patches
See https://github.com/decidim/decidim/pull/16680
Workarounds
Disable the "Identity documents" verification
Reference
OWASP A01:2021 Broken Access Control
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | decidim-verifications | all versions | 0.30.9bundle update decidim-verifications --conservative |
| 💎RubyGems | decidim-verifications | ≥ 0.31.0.rc1&&< 0.31.5 | 0.31.5bundle update decidim-verifications --conservative |
| 💎RubyGems | decidim-verifications | ≥ 0.32.0.rc1&&< 0.32.0 | 0.32.0bundle update decidim-verifications --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for decidim-verifications, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update decidim-verifications to 0.30.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3mvf-82qp-8qh5 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-3mvf-82qp-8qh5 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-3mvf-82qp-8qh5. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-3mvf-82qp-8qh5 in your dependencies?
O3 Security finds GHSA-3mvf-82qp-8qh5 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.