GHSA-w5xj-99cg-rccm

Suggest an improvement
Source
https://github.com/advisories/GHSA-w5xj-99cg-rccm
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-w5xj-99cg-rccm/GHSA-w5xj-99cg-rccm.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-w5xj-99cg-rccm
Aliases
Published
2026-04-14T22:22:58Z
Modified
2026-05-29T22:00:13Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N CVSS Calculator
Summary
Decidim amendments can be accepted or rejected by anyone
Details

Impact

The 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.

The only check done when accepting or rejecting amendments is whether the amendment reactions are enabled for the component: https://github.com/decidim/decidim/blob/9d6c3d2efe5a83bb02e095824ff5998d96a75eb7/decidim-core/app/permissions/decidim/permissions.rb#L107

The permission checks have been changed at 1b99136 which was introduced in released version 0.19.0. I have not investigated whether prior versions are also affected.

Patches

Not available

Workarounds

Disable amendment reactions for the amendable component (e.g. proposals).

Database specific 
{
    "cwe_ids":  [
        "CWE-266"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-04-14T22:22:58Z",
    "nvd_published_at":  "2026-04-21T20:17:00Z",
    "severity":  "HIGH"
}
References

Affected packages

RubyGems / decidim-core

Package

Name
decidim-core
Purl
pkg:gem/decidim-core

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0.31.0.rc1
Fixed
0.31.1

Affected versions

0.*
0.31.0.rc1
0.31.0.rc2
0.31.0

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-w5xj-99cg-rccm/GHSA-w5xj-99cg-rccm.json"

RubyGems / decidim-core

Package

Name
decidim-core
Purl
pkg:gem/decidim-core

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0.19.0
Fixed
0.30.5

Affected versions

0.*
0.19.0
0.19.1
0.20.0
0.20.1
0.21.0
0.22.0
0.23.0
0.23.1.rc1
0.23.1
0.23.2
0.23.3
0.23.4
0.23.5
0.23.6
0.24.0.rc1
0.24.0.rc2
0.24.0
0.24.1
0.24.2
0.24.3
0.25.0.rc1
0.25.0.rc2
0.25.0.rc3
0.25.0.rc4
0.25.0
0.25.1
0.25.2
0.26.0.rc1
0.26.0.rc2
0.26.0
0.26.1
0.26.2
0.26.3
0.26.4
0.26.5
0.26.7
0.26.8
0.26.9
0.26.10
0.27.0.rc1
0.27.0.rc2
0.27.0
0.27.1
0.27.2
0.27.3
0.27.4
0.27.5
0.27.6
0.27.7
0.27.8
0.27.9
0.27.10
0.28.0.rc4
0.28.0.rc5
0.28.0
0.28.1
0.28.2
0.28.3
0.28.4
0.28.5
0.28.6
0.29.0.rc1
0.29.0.rc2
0.29.0.rc3
0.29.0.rc4
0.29.0
0.29.1
0.29.2
0.29.3
0.29.4
0.29.5
0.29.6
0.29.7
0.30.0.rc1
0.30.0.rc2
0.30.0.rc3
0.30.0
0.30.1
0.30.2
0.30.3
0.30.4

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-w5xj-99cg-rccm/GHSA-w5xj-99cg-rccm.json"