Decidim's private data exports can lead to data leaks

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.2 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N · score source

EPSS

• CVE-2025-65017: 0.31% estimated exploitation activity in the next 30 days; percentile 24.32 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Private data exports can lead to data leaks in cases where the UUID generation causes collisions for the generated UUIDs. The bug was introduced by #13571 and affects Decidim versions 0.30.0 or newer (currently 2025-09-23). This issue was discovered by running the following spec several times in a row, as it can randomly fail due to this bug: Run the spec as many times as needed to hit a UUID that converts to 0 through .toi. The UUID to zero conversion does not cause a security issue but the security issue is demonstrated with the following example. The following code regenerates the issue by assigning a predefined UUID that will generate a collision (example assumes there are already two existing users in the system): Expect to see an error in the situation. Now, login as user with ID 1, go to /downloadyourdata, click "Download file" from the export and expect to see the data that should be attached to user with ID 2. This is an artificially replicated situation with the…

Published by the source

3 Feb 2026, 17:21 UTC

Last modified by the source

8 Feb 2026, 01:01 UTC

Source last checked

26 Oct 2026, 15:51 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3cx6-j9j4-54mp

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# Patch Next advisory brief: CVE-2025-65017

Advisory: Decidim's private data exports can lead to data leaks
IDs: CVE-2025-65017, GHSA-3cx6-j9j4-54mp
Record: https://patchnext.com/advisories/cve-2025-65017 (revision 1, source checked 26 Oct 2026, 15:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: decidim 0.30.4; decidim-core 0.30.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems decidim: affected >= 0.30.0, < 0.30.4; fixed in 0.30.4
- RubyGems decidim-core: affected >= 0.30.0, < 0.30.4; fixed in 0.30.4

## Suggested inspection (read-only)
- RubyGems decidim: check the installed version with your package manager.
- RubyGems decidim-core: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on decidim, decidim-core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-3cx6-j9j4-54mp (GitHub-reviewed advisory GHSA-3cx6-j9j4-54mp lists affected ranges: RubyGems decidim-core >=0.30.0 =0.30.0 <0.30.4)

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