Privilege escalation in Decidim
CVE-2026-40869
Decidim is a participatory democracy framework. Starting in version 0.19.0 and prior to versions 0.30.5 and 0.31.1, a vulnerability allows any registered and authenticated user to accept or reject any amendments. The impact is on any users who have created proposals where the amendments feature is enabled. This also elevates the user accepting the amendment as the author of the original proposal as people amending proposals are provided coauthorship on the coauthorable resources. Versions 0.30.5 and 0.31.1 fix the issue. As a workaround, disable amendment reactions for the amendable component (e.g. proposals).
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.003 (21.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 21.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Decidim — versions >= 0.31.0.rc1, < 0.31.1, >= 0.19.0, < 0.30.5
Weakness classification (CWE)
References
- github.com/decidim/decidim/security/advisories/GHSA-w5xj-99cg-rccm (Patch, Mitigation, Vendor Advisory)
- github.com/decidim/decidim/commit/1b99136a1c7aa02616a0b54a6ab88d12907a57a9 (Patch)
Frequently asked questions
- What is CVE-2026-40869?
- CVE-2026-40869 is a high-severity vulnerability in Decidim, classified under Incorrect Privilege Assignment. CVSS score: 7.5/10. Published 2026-04-21.
- How severe is CVE-2026-40869?
- High severity. CVSS v3 base score is 7.5 out of 10.