CVE-2026-45573: Decidim decidim-core SSRF in push notification subscriptions

CVE-2026-45573 · Severity: medium · CVSS 6.4 · Published 2026-08-06

Decidim, a popular open-source participatory democracy platform, contains a vulnerability in its push notification system. An authenticated user can provide a malicious web address that the server will later contact automatically when sending notifications. This could allow an attacker to probe internal network services or interact with external malicious infrastructure, potentially leading to data exposure or service disruption.

Technologies: decidim-core (RubyGems). Vendors: RubyGems.

Quick answers

Is CVE-2026-45573 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-45573 being exploited in the wild.
How severe is CVE-2026-45573?
Medium severity, with a CVSS score of 6.4, published 6 August 2026.
Which products and versions are affected?
decidim-core (RubyGems) ECOSYSTEM:introduced=0,fixed=0.30.9.
Is there a fix for CVE-2026-45573?
Yes. decidim-core (RubyGems): upgrade to 0.30.9 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-45573 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-45573?
Check whether you run decidim-core (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • decidim-core (RubyGems): upgrade to 0.30.9 or later
    bundle update decidim-core

Technical details

A stored Server-Side Request Forgery (SSRF) vulnerability exists in Decidim's push notification subscription flow. When VAPID delivery is enabled, the application fails to validate that the client-supplied 'endpoint' URL belongs to an approved push service provider. An authenticated attacker can submit a malicious HTTPS URL via a POST request to /notifications_subscriptions, which is then persisted in the user's notification settings. When a notification is subsequently triggered, the 'WebPush.payload_send' method uses this stored URL as a destination for outbound POST requests. This allows for blind SSRF against internal or external HTTPS services. The issue is fixed in versions 0.30.9, 0.31.5, and 0.32.0 by implementing an allow-list for known push providers.

Affected products

  • Decidim decidim-core < 0.30.9, >= 0.31.0.rc1, < 0.31.5, >= 0.32.0.rc1, < 0.32.0

Identifiers

  • CVE-2026-45573
  • GHSA-2g9c-vf8h-prxx

Timeline

  • 2026-05-07: patched: Pull request merged into develop branch
  • 2026-07-13: advisory: GitHub Advisory published

References

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