DecidimApplication
CVE-2023-34089
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedDecidim is a participatory democracy framework, written in Ruby on Rails, originally developed for the Barcelona City government online and offline participation website. The processes filter feature is susceptible to Cross-site scripting. This allows a remote attacker to execute JavaScript code in the context of a currently logged-in user. An attacker could use this vulnerability to make other users endorse or support proposals they have no intention of supporting or endorsing. The problem was patched in version 0.27.3 and 0.26.7.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceDecidim's processes filter feature is vulnerable to reflected cross-site scripting (XSS). An attacker can craft malicious URLs containing JavaScript payloads that execute in the context of logged-in users' browsers, potentially manipulating them to endorse or support proposals without their consent.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
DecidimApplication
< 0.26.7>= 0.27.0, < 0.27.3CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify installed Decidim versionLocate the Decidim version file or check the version through the application admin interface, or run the command to display the installed gem version (e.g., bundle show decidim or check the Gemfile.lock)Affected if The installed version is less than 0.26.7, or is 0.27.0, 0.27.1, or 0.27.2
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Confirm processes filter feature is accessibleNavigate to or identify whether the processes filter functionality is enabled in the Decidim deployment - typically found in the participatory processes section of the applicationAffected if The processes filter feature is enabled and accessible to logged-in users
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Review application access logs for malicious URL patternsSearch web server or application logs for requests to the processes filter endpoint containing suspicious script tags or javascript: patterns in URL parametersAffected if Logs contain requests with XSS payloads in the processes filter URL parameters
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Check for unauthorized proposal endorsementsAudit recent endorsements on proposals, particularly those made without the knowledge of the affected users, by reviewing the proposal endorsement records in the databaseAffected if There are endorsements on proposals that were created or cast without the explicit consent of the user accounts listed as endorsers
A user is affected if their Decidim installation version is below 0.26.7 or between 0.27.0 and 0.27.2 inclusive, and the processes filter feature is enabled.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped0.26.70.27.3
Upgrade Decidim to version 0.27.3 or 0.26.7 to remediate the XSS vulnerability in the processes filter feature.
Decidim 0.26.7 or 0.27.3 (depending on your current release line)
- Identify your current Decidim version by checking your Gemfile.lock or Gemfile
- If you are on the 0.26.x release line, upgrade to version 0.26.7
- If you are on the 0.27.x release line, upgrade to version 0.27.3
- Update your Gemfile with the appropriate version (e.g., gem 'decidim', '0.26.7' or gem 'decidim', '0.27.3')
- Run bundle install to update dependencies
- Test the upgrade in a staging environment before deploying to production
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Decidim
Scoped from the published advisory
- Consultation4.0 h
- Implementation4.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,504.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-34089 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-34089 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data