Vulnerability in Decidim Framework Allows Unauthorized Amendment Actions by Users
CVE-2026-40869

7.5HIGH

Key Information:

Vendor

Decidim

Status
Decidim
Vendor
CVE Published:
21 April 2026

What is CVE-2026-40869?

A vulnerability in the Decidim framework allows authenticated users to accept or reject amendments to proposals without proper authorization. This issue emerges in versions prior to 0.30.5 and 0.31.1, enabling users to gain coauthorship status on proposals they amend. To mitigate the risk, it is recommended to disable amendment reactions for the amendable component.

Affected Version(s)

decidim >= 0.31.0.rc1, < 0.31.1 < 0.31.0.rc1, 0.31.1

decidim >= 0.19.0, < 0.30.5 < 0.19.0, 0.30.5

References

https://github.com/decidim/decidim/security/advisories/GH...
x_refsource_CONFIRM
https://github.com/decidim/decidim/commit/1b99136a1c7aa02...
x_refsource_MISC

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.